Fixed issue where the alembic check command did not function correctly with upgrade structures that have multiple, top-level elements, as are generated from the "multi-env" environment template. Pull request courtesy Neil Williams.
Updated logic introduced in 151 to allow if_exists and if_not_exists on index operations also on SQLAlchemy 1.4 series. Previously this feature was mistakenly requiring the 2.0 series.
Replaced python-dateutil with the standard library module zoneinfo. This module was added in Python 3.9, so previous version will been to install the backport of it, available by installing the backports.zoneinfo library. The alembic[tz] option has been updated accordingly.
Alembic 1.13 now supports Python 3.8 and above.
Fixed autogenerate issue where create_table_comment() and drop_table_comment() rendering in a batch table modify would include the "table" and "schema" arguments, which are not accepted in batch as these are already part of the top level block.
Additional fixes to PostgreSQL expression index compare feature. The compare now correctly accommodates casts and differences in spacing. Added detection logic for operation clauses inside the expression, skipping the compare of these expressions. To accommodate these changes the logic for the comparison of the indexes and unique constraints was moved to the dialect implementation, allowing greater flexibility.
Fixed regression caused by 879 released in 1.7.0 where the ".info" dictionary of Table would not render in autogenerate create table statements. This can be useful for custom create table DDL rendering schemes so it is restored.
Improved typing in the .EnvironmentContext.configure.process_revision_directives callable to better indicate that the passed-in type is .MigrationScript, not the .MigrationOperation base class, and added typing to the example at cookbook_no_empty_migrations to illustrate.
Repaired .ExecuteSQLOp so that it can participate in "diff" operations; while this object is typically not present in a reflected operation stream, custom hooks may be adding this construct where it needs to have the correct to_diff_tuple() method. Pull request courtesy Sebastian Bayer.
Improved the op.execute() method to correctly accept the Executable type that is the same which is used in SQLAlchemy Connection.execute(). Pull request courtesy Mihail Milushev.
Improve typing of the revision parameter in various command functions.
Properly type the .Operations.create_check_constraint.condition parameter of .Operations.create_check_constraint to accept boolean expressions.
Fixed autogen render issue where expressions inside of indexes for PG need to be double-parenthesized, meaning a single parens must be present within the generated text() construct.
Alembic now accommodates for Sequence and Identity that support dialect kwargs. This is a change that will be added to SQLAlchemy v2.1.
Added support for op.drop_constraint() to support PostgreSQL ExcludeConstraint objects, as well as other constraint-like objects that may be present in third party dialects, by resolving the type_ parameter to be None for this case. Autogenerate has also been enhanced to exclude the type_ parameter from rendering within this command when type_ is None. Pull request courtesy David Hills.
Fixed issue where the revision_environment directive in alembic.ini was ignored by the alembic merge command, leading to issues when other configurational elements depend upon env.py being invoked within the command.
Fixed issue where the ForeignKeyConstraint.match parameter would not be rendered in autogenerated migrations. Pull request courtesy Asib Kamalsada.
Change the default value of .EnvironmentContext.configure.compare_type to True. As Alembic's autogenerate for types was dramatically improved in version 1.4 released in 2020, the type comparison feature is now much more reliable so is now enabled by default.
Added new feature to the "code formatter" function which allows standalone executable tools to be run against code, without going through the Python interpreter. Known as the exec runner, it complements the existing console_scripts runner by allowing non-Python tools such as ruff to be used. Pull request courtesy Mihail Milushev.
post_write_hooks_config
Improved autogenerate compare of expression based indexes on PostgreSQL to produce fewer wrong detections.
Fixed issue with NULLS NOT DISTINCT detection in postgresql that would keep detecting changes in the index or unique constraint.
Added encoding="locale" setting to the use of Python's ConfigParser.read(), so that a warning is not generated when using the recently added Python feature PYTHONWARNDEFAULTENCODING specified in 597. The encoding is passed as the "locale" string under Python 3.10 and greater, which indicates that the system-level locale should be used, as was the case already here. Pull request courtesy Kevin Kirsche.
Added typing to the default script mako templates.
Added support in autogenerate for NULLS NOT DISTINCT in the PostgreSQL dialect.
Fixed format string logged when running a post write hook Pull request curtesy of Mathieu Défosse.
Added parameters if_exists and if_not_exists for index operations. Pull request courtesy of Max Adrian.
As Alembic 1.11.0 is considered a major release (Alembic does not use semver, nor does its parent project SQLAlchemy; this has been clarified <versioning_scheme> in the documentation), change 1130 modified calling signatures for most operations to consider all optional keyword parameters to be keyword-only arguments, to match what was always documented and generated by autogenerate. However, two of these changes were identified as possibly problematic without a more formal deprecation warning being emitted which were the table_name parameter to .Operations.drop_index, which was generated positionally by autogenerate prior to version 0.6.3 released in 2014, and type_ in .Operations.drop_constraint and .BatchOperations.drop_constraint, which was documented positionally in one example in the batch documentation.
These two signatures have been restored to allow those particular parameters to be passed positionally. A future change will include formal deprecation paths (with warnings) for these arguments where they will again become keyword-only in a future "Significant Minor" release.
Fixed typing use of ~sqlalchemy.schema.Column and other generic SQLAlchemy classes.
Restored the output type of .Config.get_section to include Dict[str, str] as a potential return type, which had been changed to immutable Mapping[str, str]. When a section is returned and the default is not used, a mutable dictionary is returned.
Added placeholder classes for ~.sqla.Computed and ~.sqla.Identity when older 1.x SQLAlchemy versions are in use, namely prior to SQLAlchemy 1.3.11 when the ~.sqla.Computed construct was introduced. Previously these were set to None, however this could cause issues with certain codepaths that were using isinstance() such as one within "batch mode".
Correctly pass previously ignored arguments insert_before and insert_after in batch_alter_column
Argument signatures of Alembic operations now enforce keyword-only arguments as passed as keyword and not positionally, such as .Operations.create_table.schema, .Operations.add_column.type_, etc.
Fix autogenerate issue with PostgreSQL .ExcludeConstraint that included sqlalchemy functions. The function text was previously rendered as a plain string without surrounding with text().
Fixed regression caused by 1166 released in version 1.10.0 which caused MySQL unique constraints with multiple columns to not compare correctly within autogenerate, due to different sorting rules on unique constraints vs. indexes, which in MySQL are shared constructs.
Update code snippets within docstrings to use black code formatting. Pull request courtesy of James Addison.
Updated stub generator script to also add stubs method definitions for the .Operations class and the .BatchOperations class obtained from .Operations.batch_alter_table. As part of this change, the class hierarchy of .Operations and .BatchOperations has been rearranged on top of a common base class .AbstractOperations in order to type correctly, as .BatchOperations uses different method signatures for operations than .Operations.
Repaired the return signatures for .Operations that mostly return None, and were erroneously referring to Optional[Table] in many cases.
Added quiet option to the command line, using the -q/--quiet option. This flag will prevent alembic from logging anything to stdout.
Modified the autogenerate implementation for comparing "server default" values from user-defined metadata to not apply any quoting to the value before comparing it to the server-reported default, except for within dialect-specific routines as needed. This change will affect the format of the server default as passed to the .EnvironmentContext.configure.compare_server_default hook, as well as for third party dialects that implement a custom compare_server_default hook in their alembic impl, to be passed "as is" and not including additional quoting. Custom implementations which rely on this quoting should adjust their approach based on observed formatting.
Fixed issue where .autogenerate.render_python_code function did not provide a default value for the user_module_prefix variable, leading to NoneType errors when autogenerate structures included user-defined types. Added new parameter .autogenerate.render_python_code.user_module_prefix to allow this to be set as well as to default to None. Pull request courtesy tangkikodo.
Added .AbstractOperations.run_async to the operation module to allow running async functions in the upgrade or downgrade migration function when running alembic using an async dialect. This function will receive as first argument an ~sqlalchemy.ext.asyncio.AsyncConnection sharing the transaction used in the migration context.
Added support for autogenerate comparison of indexes on PostgreSQL which include SQL sort option, such as ASC or NULLS FIRST. The sort options are correctly detected only when defined using the sqlalchemy modifier functions, such as asc() or nulls_first(), or the equivalent methods. Passing sort options inside the postgresql_ops dict is not supported.
Fixed issue where using a directive such as op.create_foreign_key() to create a self-referential constraint on a single table where the same column were present on both sides (e.g. within a composite foreign key) would produce an error under SQLAlchemy 2.0 and a warning under SQLAlchemy 1.4 indicating that a duplicate column were being added to a table.
Fixed various typing issues observed with pyright, including issues involving the combination of .Function and .MigrationContext.begin_transaction.
Fixed error raised by alembic when running autogenerate after removing a function based index.
Fixed regression where Alembic would not run with older SQLAlchemy 1.3 versions prior to 1.3.24 due to a missing symbol. Workarounds have been applied for older 1.3 versions.
Fixed issue regarding PostgreSQL .ExcludeConstraint, where constraint elements which made use of .literal_column could not be rendered for autogenerate. Additionally, using SQLAlchemy 2.0.5 or greater, .text() constructs are also supported within PostgreSQL .ExcludeConstraint objects for autogenerate render. Pull request courtesy Jan Katins.
Fixed regression for 1.10.0 where .Constraint objects were suddenly required to have non-None name fields when using batch mode, which was not previously a requirement.
Fixed issue in index detection where autogenerate change detection would consider indexes with the same columns but with different order as equal, while in general they are not equivalent in how a database will use them.
Recursive traversal of revision files in a particular revision directory is now supported, by indicating recursive_version_locations = true in alembic.ini. Pull request courtesy ostr00000.
Fixed issue where indexes on SQLite which include SQL expressions would not compare correctly, generating false positives under autogenerate. These indexes are now skipped, generating a warning, in the same way that expression-based indexes on PostgreSQL are skipped and generate warnings when SQLAlchemy 1.x installations are in use. Note that reflection of SQLite expression-based indexes continues to not yet be supported under SQLAlchemy 2.0, even though PostgreSQL expression-based indexes have now been implemented.
Properly escape constraint name on SQL Server when dropping a column while specifying mssql_drop_default=True or mssql_drop_check=True or mssql_drop_foreign_key=True.
Added support for autogenerate comparison of indexes on PostgreSQL which include SQL expressions, when using SQLAlchemy 2.0; the previous warning that such indexes were skipped are removed when the new functionality is in use. When using SQLAlchemy versions prior to the 2.0 series, the indexes continue to be skipped with a warning.
Ongoing fixes for SQL Server server default comparisons under autogenerate, adjusting for SQL Server's collapsing of whitespace between SQL function arguments when reporting on a function-based server default, as well as its arbitrary addition of parenthesis within arguments; the approach has now been made more aggressive by stripping the two default strings to compare of all whitespace, parenthesis, and quoting characters.
Fixed PostgreSQL server default comparison to handle SQL expressions sent as text() constructs, such as text("substring('name', 1, 3)"), which previously would raise errors when attempting to run a server-based comparison.
Removed a mis-use of the .EnvironmentContext.configure.render_item callable where the "server_default" renderer would be erroneously used within the server default comparison process, which is working against SQL expressions, not Python code.
Fixed regression introduced in 1.7.0 where the "config" object passed to the template context when running the .merge command programmatically failed to be correctly populated. Pull request courtesy Brendan Gann.
Fixed issue where rendering of user-defined types that then went onto use the .with_variant() method would fail to render, if using SQLAlchemy 2.0's version of variants.
Fixed typing definitions for .EnvironmentContext.get_x_argument.
Typing stubs are now generated for overloaded proxied methods such as .EnvironmentContext.get_x_argument.
Fixed regression caused by 1145 where the string transformations applied to server defaults caused expressions such as (getdate()) to no longer compare as equivalent on SQL Server, others.
Fixed issue where server default compare would not work for string defaults that contained backslashes, due to mis-rendering of these values when comparing their contents.
Implemented basic server default comparison for the Oracle backend; previously, Oracle's formatting of reflected defaults prevented any matches from occurring.
Adjusted SQLite's compare server default implementation to better handle defaults with or without parens around them, from both the reflected and the local metadata side.
Adjusted SQL Server's compare server default implementation to better handle defaults with or without parens around them, from both the reflected and the local metadata side.
Added new Alembic command alembic check. This performs the widely requested feature of running an "autogenerate" comparison between the current database and the .MetaData that's currently set up for autogenerate, returning an error code if the two do not match, based on current autogenerate settings. Pull request courtesy Nathan Louie.
alembic_check
Fixed issue in tox.ini file where changes in the tox 4.0 series to the format of "passenv" caused tox to not function correctly, in particular raising an error as of tox 4.0.6.
Fixed typing issue where .revision.process_revision_directives was not fully typed; additionally ensured all Callable and Dict arguments to .EnvironmentContext.configure include parameters in the typing declaration.
Additionally updated the codebase for Mypy 0.990 compliance.
Fixed bug where the SQLite implementation of .Operations.rename_table would render an explicit schema name for both the old and new table name, which while is the standard ALTER syntax, is not accepted by SQLite's syntax which doesn't support a rename across schemas. In particular, the syntax issue would prevent batch mode from working for SQLite databases that made use of attached databases (which are treated as "schemas" in SQLAlchemy).
Added an error raise for the condition where .Operations.batch_alter_table is used in --sql mode, where the operation requires table reflection, as is the case when running against SQLite without giving it a fixed Table object. Previously the operation would fail with an internal error. To get a "move and copy" batch operation as a SQL script without connecting to a database, a Table object should be passed to the .Operations.batch_alter_table.copy_from parameter so that reflection may be skipped.
484 typing annotations have been added to the env.py and revision template files within migration templates. Pull request by Nikita Sobolev.
The op.drop_table() operation directive will now trigger the before_drop() and after_drop() DDL event hooks at the table level, which is similar to how the before_create() and after_create() hooks are triggered by the op.create_table() directive. Note that as op.drop_table() accepts only a table name and optional schema name, the Table object received by the event will not have any information within it other than the table name and schema name.
Alembic 1.8 now supports Python 3.7 and above.
The "Pylons" environment template has been removed as of Alembic 1.8. This template was based on the very old pre-Pyramid Pylons web framework which has been long superseded by Pyramid.
Fixed issue where a downgrade using a relative revision would fail in case of multiple branches with a single effectively head due to interdependencies between revisions.
Added new token epoch to the file_template option, which will populate the integer epoch as determined by int(create_date.timestamp()). Pull request courtesy Caio Carvalho.
Fixed issue in batch mode where CREATE INDEX would not use a new column name in the case of a column rename.
Fixed issue where using .Operations.create_table in conjunction with a .CheckConstraint that referred to table-bound .Column objects rather than string expressions would be added to the parent table potentially multiple times, resulting in an incorrect DDL sequence. Pull request courtesy Nicolas CANIART.
The logging.fileConfig() line in env.py templates, which is used to setup Python logging for the migration run, is now conditional on .Config.config_file_name not being None. Otherwise, the line is skipped as there is no default logging configuration present.
Fixed bug where an .Operations.alter_column operation would change a "NOT NULL" column to "NULL" by emitting an ALTER COLUMN statement that did not specify "NOT NULL". (In the absence of "NOT NULL" T-SQL was implicitly assuming "NULL"). An .Operations.alter_column operation that specifies .Operations.alter_column.type should also specify include either .Operations.alter_column.nullable or .Operations.alter_column.existing_nullable to inform Alembic as to whether the emitted DDL should include "NULL" or "NOT NULL"; a warning is now emitted if this is missing under this scenario.
Fixed regression where usage of a with_variant() datatype in conjunction with the existing_type option of op.alter_column() under batch mode would lead to an internal exception.
Add a new command alembic ensure_version, which will ensure that the Alembic version table is present in the target database, but does not alter its contents. Pull request courtesy Kai Mueller.
Implemented support for recognizing and rendering SQLAlchemy "variant" types going forward into SQLAlchemy 2.0, where the architecture of "variant" datatypes will be changing.
Added a rule to the MySQL impl so that the translation between JSON / LONGTEXT is accommodated by autogenerate, treating LONGTEXT from the server as equivalent to an existing JSON in the model.
Removed a warning raised by SQLAlchemy when dropping constraints on MSSQL regarding statement caching.
Adjustments to the test suite to accommodate for error message changes occurring as of SQLAlchemy 1.4.27.
Fixed a regression that prevented the use of post write hooks on python version lower than 3.9
Fixed issue where the .MigrationContext.autocommit_block feature would fail to function when using a SQLAlchemy engine using 2.0 future mode.
Fixed type annotations for the "constraint_name" argument of operations create_primary_key(), create_foreign_key(). Pull request courtesy TilmanK.
Added missing attributes from context stubs.
Fixed an import in one of the .pyi files that was triggering an assertion error in some versions of mypy.
Fixed issue where registration of custom ops was prone to failure due to the registration process running exec() on generated code that as of the 1.7 series includes pep-484 annotations, which in the case of end user code would result in name resolution errors when the exec occurs. The logic in question has been altered so that the annotations are rendered as forward references so that the exec() can proceed.
Corrected "universal wheel" directive in setup.cfg so that building a wheel does not target Python 2. The PyPi files index for 1.7.0 was corrected manually. Pull request courtesy layday.
Fixed issue in generated .pyi files where default values for Optional arguments were missing, thereby causing mypy to consider them as required.
Fixed regression in batch mode due to 883 where the "auto" mode of batch would fail to accommodate any additional migration directives beyond encountering an add_column() directive, due to a mis-application of the conditional logic that was added as part of this change, leading to "recreate" mode not being used in cases where it is required for SQLite such as for unique constraints.
Fixed regression due to 803 where the .info and .comment attributes of Table would be lost inside of the .DropTableOp class, which when "reversed" into a .CreateTableOp would then have lost these elements. Pull request courtesy Nicolas CANIART.
Enhance version_locations parsing to handle paths containing spaces. The new configuration option version_path_separator specifies the character to use when splitting the version_locations string. The default for new configurations is version_path_separator = os, which will use os.pathsep (e.g., ; on Windows).
Alembic 1.7 now supports Python 3.6 and above; support for prior versions including Python 2.7 has been dropped.
Batch "auto" mode will now select for "recreate" if the add_column() operation is used on SQLite, and the column itself meets the criteria for SQLite where ADD COLUMN is not allowed, in this case a functional or parenthesized SQL expression or a Computed (i.e. generated) column.
Make the python-dateutil library an optional dependency. This library is only required if the timezone option is used in the Alembic configuration. An extra require named tz is available with pip install alembic[tz] to install it.
Re-implemented the python-editor dependency as a small internal function to avoid the need for external dependencies.
Named CHECK constraints are now supported by batch mode, and will automatically be part of the recreated table assuming they are named. They also can be explicitly dropped using op.drop_constraint(). For "unnamed" CHECK constraints, these are still skipped as they cannot be distinguished from the CHECK constraints that are generated by the Boolean and Enum datatypes.
Note that this change may require adjustments to migrations that drop or rename columns which feature an associated named check constraint, such that an additional op.drop_constraint() directive should be added for that named constraint as there will no longer be an associated column for it; for the Boolean and Enum datatypes, an existing_type keyword may be passed to BatchOperations.drop_constraint as well.
batch_schematype_constraints
batch_check_constraints
The dependency on pkg_resources which is part of setuptools has been removed, so there is no longer any runtime dependency on setuptools. The functionality has been replaced with importlib.metadata and importlib.resources which are both part of Python std.lib, or via pypy dependency importlib-metadata for Python version < 3.8 and importlib-resources for Python version < 3.9 (while importlib.resources was added to Python in 3.7, it did not include the "files" API until 3.9).
Created a "test suite" similar to the one for SQLAlchemy, allowing developers of third-party dialects to test their code against a set of Alembic tests that have been specially selected to exercise back-end database operations. At the time of release, third-party dialects that have adopted the Alembic test suite to verify compatibility include CockroachDB and SAP ASE (Sybase).
Fixed issue where usage of the PostgreSQL postgresql_include option within a .Operations.create_index would raise a KeyError, as the additional column(s) need to be added to the table object used by the construct internally. The issue is equivalent to the SQL Server issue fixed in 513. Pull request courtesy Steven Bronson.
pep-484 type annotations have been added throughout the library. Additionally, stub .pyi files have been added for the "dynamically" generated Alembic modules alembic.op and alembic.config, which include complete function signatures and docstrings, so that the functions in these namespaces will have both IDE support (vscode, pycharm, etc) as well as support for typing tools like Mypy. The files themselves are statically generated from their source functions within the source tree.
Fixed issue where dialect-specific keyword arguments within the .DropIndex operation directive would not render in the autogenerated Python code. As support was improved for adding dialect specific arguments to directives as part of 803, in particular arguments such as "postgresql_concurrently" which apply to the actual create/drop of the index, support was needed for these to render even in a drop index operation. Pull request courtesy Jet Zhou.
Fixed regression caused by just fixed 844 that scaled back the filter for unique=True/index=True too far such that these directives no longer worked for the op.create_table() op, this has been fixed.
Fixed 1.6-series regression where UniqueConstraint and to a lesser extent Index objects would be doubled up in the generated model when the unique=True / index=True flags were used.
Fixed a bug where paths defined in post-write hook options would be wrongly escaped in non posix environment (Windows).
Fixed regression where a revision file that contained its own down revision as a dependency would cause an endless loop in the traversal logic.
Fixed additional regression nearly the same as that of 838 just released in 1.6.1 but within a slightly different codepath, where "alembic downgrade head" (or equivalent) would fail instead of iterating no revisions.
Fixed regression in new revisioning traversal where "alembic downgrade base" would fail if the database itself were clean and unversioned; additionally repairs the case where downgrade would fail if attempting to downgrade to the current head that is already present.
Refactored the implementation of .MigrateOperation constructs such as .CreateIndexOp, .CreateTableOp, etc. so that they no longer rely upon maintaining a persistent version of each schema object internally; instead, the state variables of each operation object will be used to produce the corresponding construct when the operation is invoked. The rationale is so that environments which make use of operation-manipulation schemes such as those discussed in autogen_rewriter are better supported, allowing end-user code to manipulate the public attributes of these objects which will then be expressed in the final output, an example is some_create_index_op.kw["postgresql_concurrently"] = True.
Previously, these objects when generated from autogenerate would typically hold onto the original, reflected element internally without honoring the other state variables of each construct, preventing the public API from working.
Fixed regression caused by the SQLAlchemy 1.4/2.0 compatibility switch where calling .rollback() or .commit() explicitly within the context.begin_transaction() context manager would cause it to fail when the block ended, as it did not expect that the transaction was manually closed.
Improved the rendering of op.add_column() operations when adding multiple columns to an existing table, so that the order of these statements matches the order in which the columns were declared in the application's table metadata. Previously the added columns were being sorted alphabetically.
Fix the documentation regarding the default command-line argument position of the revision script filename within the post-write hook arguments. Implement a REVISION_SCRIPT_FILENAME token, enabling the position to be changed. Switch from str.split() to shlex.split() for more robust command-line argument parsing.
Implement a .cwd (current working directory) suboption for post-write hooks (of type console_scripts). This is useful for tools like pre-commit, which rely on the working directory to locate the necessary config files. Add pre-commit as an example to the documentation. Minor change: rename some variables from ticket #819 to improve readability.
The algorithm used for calculating downgrades/upgrades/iterating revisions has been rewritten, to resolve ongoing issues of branches not being handled consistently particularly within downgrade operations, as well as for overall clarity and maintainability. This change includes that a deprecation warning is emitted if an ambiguous command such as "downgrade -1" when multiple heads are present is given.
In particular, the change implements a long-requested use case of allowing downgrades of a single branch to a branchpoint.
Huge thanks to Simon Bowly for their impressive efforts in successfully tackling this very difficult problem.
Added missing batch_op.create_table_comment(), batch_op.drop_table_comment() directives to batch ops.
Fixed regression caused by SQLAlchemy 1.4 where the "alembic current" command would fail due to changes in the URL object.
Adjusted the recently added .EnvironmentContext.configure.include_name hook to accommodate for additional object types such as "views" that don't have a parent table, to support third party recipes and extensions. Pull request courtesy Oliver Rice.
Fixed bug where the "existing_type" parameter, which the MSSQL dialect requires in order to change the nullability of a column in the absence of also changing the column type, would cause an ALTER COLUMN operation to incorrectly render a second ALTER statement without the nullability if a new type were also present, as the MSSQL-specific contract did not anticipate all three of "nullability", "type_" and "existing_type" being sent at the same time.
Add async template to Alembic to bootstrap environments that use async DBAPI. Updated the cookbook to include a migration guide on how to adapt an existing environment for use with DBAPI drivers.
Adjusted the use of SQLAlchemy's ".copy()" internals to use "._copy()" for version 1.4.0, as this method is being renamed.
Added new config file option prepend_sys_path, which is a series of paths that will be prepended to sys.path; the default value in newly generated alembic.ini files is ".". This fixes a long-standing issue where for some reason running the alembic command line would not place the local "." path in sys.path, meaning an application locally present in "." and importable through normal channels, e.g. python interpreter, pytest, etc. would not be located by Alembic, even though the env.py file is loaded relative to the current path when alembic.ini contains a relative path. To enable for existing installations, add the option to the alembic.ini file as follows:
# sys.path path, will be prepended to sys.path if present.
# defaults to the current working directory.
prepend_sys_path = .installation - updated documentation reflecting that local installation of the project is not necessary if running the Alembic cli from the local path.
Fixed bug in versioning model where a downgrade across a revision with a dependency on another branch, yet an ancestor is also dependent on that branch, would produce an erroneous state in the alembic_version table, making upgrades impossible without manually repairing the table.
Changed the default ordering of "CREATE" and "DROP" statements indexes and unique constraints within the autogenerate process, so that for example in an upgrade() operation, a particular index or constraint that is to be replaced such as for a casing convention change will not produce any naming conflicts. For foreign key constraint objects, this is already how constraints are ordered, and for table objects, users would normally want to use .Operations.rename_table in any case.
Fixed assorted autogenerate issues with SQL Server:
- ignore default reflected identity on primary_key columns
- improve server default comparison
Fixed issue where autogenerate rendering of op.alter_column() would fail to include MySQL existing_nullable=False if the column were part of a primary key constraint within the table metadata.
Fixed regression where new "loop detection" feature introduced in 757 produced false positives for revision names that have overlapping substrings between revision number and down revision and/or dependency, if the downrev/dependency were not in sequence form.
Fixed regression where Alembic would fail to create a transaction properly if the sqlalchemy.engine.Connection were a so-called "branched" connection, that is, one where the .connect() method had been called to create a "sub" connection.
Fixed installation issue where the "templates" directory was not being installed, preventing commands like "list_templates" and "init" from working.
Added support for rendering of "identity" elements on .Column objects, supported in SQLAlchemy via the .Identity element introduced in version 1.4.
Adding columns with identity is supported on PostgreSQL, MSSQL and Oracle. Changing the identity options or removing it is supported only on PostgreSQL and Oracle.
To accommodate SQLAlchemy 1.4 and 2.0, the migration model now no longer assumes that the SQLAlchemy Connection will autocommit an individual operation. This essentially means that for databases that use non-transactional DDL (pysqlite current driver behavior, MySQL), there is still a BEGIN/COMMIT block that will surround each individual migration. Databases that support transactional DDL should continue to have the same flow, either per migration or per-entire run, depending on the value of the .Environment.configure.transaction_per_migration flag.
A .CommandError is raised if a sqlalchemy.engine.Engine is passed to the .MigrationContext.configure method instead of a sqlalchemy.engine.Connection object. Previously, this would be a warning only.
Modified the add_column() operation such that the Column object in use is shallow copied to a new instance if that Column is already attached to a table() or Table. This accommodates for the change made in SQLAlchemy issue #5618 which prohibits a Column from being associated with multiple table() objects. This resumes support for using a Column inside of an Alembic operation that already refers to a parent table() or Table as well as allows operation objects just autogenerated to work.
Added new hook .EnvironmentContext.configure.include_name, which complements the .EnvironmentContext.configure.include_object hook by providing a means of preventing objects of a certain name from being autogenerated before the SQLAlchemy reflection process takes place, and notably includes explicit support for passing each schema name when .EnvironmentContext.configure.include_schemas is set to True. This is most important especially for environments that make use of .EnvironmentContext.configure.include_schemas where schemas are actually databases (e.g. MySQL) in order to prevent reflection sweeps of the entire server.
autogenerate_include_hooks - new documentation section
The long deprecated .EnvironmentContext.configure.include_symbol hook is removed. The .EnvironmentContext.configure.include_object and .EnvironmentContext.configure.include_name hooks both achieve the goals of this hook.
Added rendering for the Table.prefixes element to autogenerate so that the rendered Python code includes these directives. Pull request courtesy Rodrigo Ce Moretto.
Added missing "create comment" feature for columns that are altered in batch migrations.
Alembic 1.5.0 now supports Python 2.7 and Python 3.6 and above, as well as SQLAlchemy 1.3.0 and above. Support is removed for Python 3 versions prior to 3.6 and SQLAlchemy versions prior to the 1.3 series.
Made an adjustment to the PostgreSQL dialect to allow it to work more effectively in batch mode, where a datatype like Boolean or non-native Enum that may have embedded rules to generate CHECK constraints will be more correctly handled in that these constraints usually will not have been generated on the PostgreSQL backend; previously it would inadvertently assume they existed unconditionally in a special PG-only "drop constraint" step.
The revision tree is now checked for cycles and loops between revision files when the revision environment is loaded up. Scenarios such as a revision pointing to itself, or a revision that can reach itself via a loop, are handled and will raise the .CycleDetected exception when the environment is loaded (expressed from the Alembic commandline as a failure message and nonzero return code). Previously, these situations were silently ignored up front, and the behavior of revision traversal would either be silently incorrect, or would produce errors such as .RangeNotAncestorError. Pull request courtesy Koichiro Den.
Add __main__.py file to alembic package to support invocation with python -m alembic.
Removed deprecated --head_only option to the alembic current command
Removed legacy parameter names from operations, these have been emitting warnings since version 0.8. In the case that legacy version files have not yet been updated, these can be modified directly in order to maintain compatibility:
.Operations.drop_constraint- "type" (use"type_") and "name" (use "constraint_name").Operations.create_primary_key- "cols" (use "columns") and "name" (use "constraint_name").Operations.create_unique_constraint- "name" (use "constraint_name"), "source" (use "table_name") and "local_cols" (use "columns").Operations.batch_create_unique_constraint- "name" (use "constraint_name").Operations.create_foreign_key- "name" (use "constraint_name"), "source" (use "source_table"), "referent" (use "referent_table").Operations.batch_create_foreign_key- "name" (use "constraint_name"), "referent" (use "referent_table").Operations.create_check_constraint- "name" (use "constraint_name"), "source" (use "table_name").Operations.batch_create_check_constraint- "name" (use "constraint_name").Operations.create_index- "name" (use "index_name").Operations.drop_index- "name" (use "index_name"), "tablename" (use "table_name").Operations.batch_drop_index- "name" (use "index_name"),.Operations.create_table- "name" (use "table_name").Operations.drop_table- "name" (use "table_name").Operations.alter_column- "name" (use "new_column_name")
Added support to drop named CHECK constraints that are specified as part of a column, rather than table wide. Previously, only constraints associated with the table were considered.
Fixed issue where the MySQL dialect would not correctly render the server default of a column in an alter operation, if the operation were programmatically generated from an autogenerate pass as it would not accommodate for the full structure of the DefaultClause construct.
Fixed issue where the CAST applied to a JSON column when copying a SQLite table during batch mode would cause the data to be lost, as SQLite's CAST with JSON appears to convert the data to the value "0". The CAST is now skipped in a dialect-specific manner, including for JSON columns on SQLite. Pull request courtesy Sebastián Ramírez.
The alembic current command no longer creates an alembic_version table in the database if one does not exist already, returning no version as the current version. This allows checking for migrations in parallel without introducing race conditions. Pull request courtesy Nikolay Edigaryev.
Fixed issue where columns in a foreign-key referenced table would be replaced with null-type columns during a batch operation; while this did not generally have any side effects, it could theoretically impact a batch operation that also targets that table directly and also would interfere with future changes to the .append_column() method to disallow implicit replacement of columns.
Fixed issue where the mssql_drop_foreign_key=True flag on op.drop_column would lead to incorrect syntax error due to a typo in the SQL emitted, same typo was present in the test as well so it was not detected. Pull request courtesy Oleg Shigorin.
Adjusted autogen comparison to accommodate for backends that support computed column reflection, dependent on SQLAlchemy version 1.3.16 or higher. This emits a warning if the SQL expression inside of a .Computed value changes between the metadata and the database, as these expressions can't be changed without dropping and recreating the column.
Fixed an issue that prevented the test suite from running with the recently released py.test 5.4.0.
Fixed more false-positive failures produced by the new "compare type" logic first added in 605, particularly impacting MySQL string types regarding flags such as "charset" and "collation".
Fixed issue in Oracle backend where a table RENAME with a schema-qualified name would include the schema in the "to" portion, which is rejected by Oracle.
Fixed regression caused by the new "type comparison" logic introduced in 1.4 as part of 605 where comparisons of MySQL "unsigned integer" datatypes would produce false positives, as the regular expression logic was not correctly parsing the "unsigned" token when MySQL's default display width would be returned by the database. Pull request courtesy Paul Becotte.
Error message for "path doesn't exist" when loading up script environment now displays the absolute path. Pull request courtesy Rowan Hart.
Fixed regression in 1.4.0 due to 647 where unique constraint comparison with mixed case constraint names while not using a naming convention would produce false positives during autogenerate.
The check for matched rowcount when the alembic_version table is updated or deleted from is now conditional based on whether or not the dialect supports the concept of "rowcount" for UPDATE or DELETE rows matched. Some third party dialects do not support this concept. Pull request courtesy Ke Zhu.
Fixed long-standing bug where an inline column CHECK constraint would not be rendered within an "ADD COLUMN" operation. The DDL compiler is now consulted for inline constraints within the .Operations.add_column method as is done for regular CREATE TABLE operations.
The internal inspection routines no longer use SQLAlchemy's Inspector.from_engine() method, which is expected to be deprecated in 1.4. The inspect() function is now used.
Adjusted the unique constraint comparison logic in a similar manner as that of 421 did for indexes in order to take into account SQLAlchemy's own truncation of long constraint names when a naming convention is in use. Without this step, a name that is truncated by SQLAlchemy based on a unique constraint naming convention or hardcoded name will not compare properly.
Added new parameters .BatchOperations.add_column.insert_before, .BatchOperations.add_column.insert_after which provide for establishing the specific position in which a new column should be placed. Also added .Operations.batch_alter_table.partial_reordering which allows the complete set of columns to be reordered when the new table is created. Both operations apply only to when batch mode is recreating the whole table using recreate="always". Thanks to Marcin Szymanski for assistance with the implementation.
Moved the use of the __file__ attribute at the base of the Alembic package into the one place that it is specifically needed, which is when the config attempts to locate the template directory. This helps to allow Alembic to be fully importable in environments that are using Python memory-only import schemes. Pull request courtesy layday.
A major rework of the "type comparison" logic is in place which changes the entire approach by which column datatypes are compared. Types are now compared based on the DDL string generated by the metadata type vs. the datatype reflected from the database. This means we compare types based on what would actually render and additionally if elements of the types change like string length, those changes are detected as well. False positives like those generated between SQLAlchemy Boolean and MySQL TINYINT should also be resolved. Thanks very much to Paul Becotte for lots of hard work and patience on this one.
Note
updated - this change also removes support for the compare_against_backend SQLAlchemy type hook.
autogenerate_detects - updated comments on type comparison
Fixed issue where COMMENT directives for PostgreSQL failed to correctly include an explicit schema name, as well as correct quoting rules for schema, table, and column names. Pull request courtesy Matthew Sills.
Added support for rendering of "computed" elements on .Column objects, supported in SQLAlchemy via the new .Computed element introduced in version 1.3.11. Pull request courtesy Federico Caselli.
Note that there is currently no support for ALTER COLUMN to add, remove, or modify the "GENERATED ALWAYS AS" element from a column; at least for PostgreSQL, it does not seem to be supported by the database. Additionally, SQLAlchemy does not currently reliably reflect the "GENERATED ALWAYS AS" phrase from an existing column, so there is also no autogenerate support for addition or removal of the .Computed element to or from an existing column, there is only support for adding new columns that include the .Computed element. In the case that the .Computed element is removed from the .Column object in the table metadata, PostgreSQL and Oracle currently reflect the "GENERATED ALWAYS AS" expression as the "server default" which will produce an op that tries to drop the element as a default.
Fixed regression introduced by 579 where server default rendering functions began to require a dialect implementation, however the .render_python_code convenience function did not include one, thus causing the function to fail when used in a server default context. The function now accepts a migration context argument and also creates one against the default dialect if one is not provided.
Fixed bug in MSSQL dialect where the drop constraint execution steps used to remove server default or implicit foreign key constraint failed to take into account the schema name of the target table.
Added support for ALEMBIC_CONFIG environment variable, refers to the location of the alembic configuration script in lieu of using the -c command line option.
Fixed bug in new Variant autogenerate where the order of the arguments to Variant were mistakenly reversed.
Some internal modifications have been made to how the names of indexes and unique constraints work to make use of new functions added in SQLAlchemy 1.4, so that SQLAlchemy has more flexibility over how naming conventions may be applied to these objects.
Reverted the name change of the "revisions" argument to .command.stamp to "revision" as apparently applications are calling upon this argument as a keyword name. Pull request courtesy Thomas Bechtold. Special translations are also added to the command line interface so that it is still known as "revisions" in the CLI.
Removed the "test requirements" from "setup.py test", as this command now only emits a removal error in any case and these requirements are unused.
Added new --purge flag to the alembic stamp command, which will unconditionally erase the version table before stamping anything. This is useful for development where non-existent version identifiers might be left within the table. Additionally, alembic.stamp now supports a list of revision identifiers, which are intended to allow setting up multiple heads at once. Overall handling of version identifiers within the alembic.stamp command has been improved with many new tests and use cases added.
Improved the Python rendering of a series of migration operations such that a single "pass" is rendered for a .UpgradeOps or .DowngradeOps based on if no lines of Python code actually rendered under the operation, rather than whether or not sub-directives exist. Removed extra "pass" lines that would generate from the .ModifyTableOps directive so that these aren't duplicated under operation rewriting scenarios.
Added new feature .MigrationContext.autocommit_block, a special directive which will provide for a non-transactional block inside of a migration script. The feature requires that: the database driver (e.g. DBAPI) supports the AUTOCOMMIT isolation mode. The directive also necessarily needs to COMMIT the existing transaction in progress in order to enter autocommit mode.
.MigrationContext.autocommit_block
Python 3.4 support is dropped, as the upstream tooling (pip, mysqlclient) etc are already dropping support for Python 3.4, which itself is no longer maintained.
Added autogenerate support for .Column objects that have dialect-specific **kwargs, support first added in SQLAlchemy 1.3. This includes SQLite "on conflict" as well as options used by some third party dialects.
Added rendering for SQLAlchemy Variant datatypes, which render as the base type plus one or more .with_variant() method calls.
Made the command interface revision lookup behavior more strict in that an Alembic revision number is only resolved based on a partial match rules if it has at least four characters, to prevent simple typographical issues from inadvertently running migrations.
Added "post write hooks" to revision generation. These allow custom logic to run after a revision Python script is generated, typically for the purpose of running code formatters such as "Black" or "autopep8", but may be used for any arbitrary post-render hook as well, including custom Python functions or scripts. The hooks are enabled by providing a
[post_write_hooks]section in the alembic.ini file. A single hook is provided which runs an arbitrary Python executable on the newly generated revision script, which can be configured to run code formatters such as Black; full examples are included in the documentation.
post_write_hooks
Added new flag --package to alembic init. For environments where the Alembic migration files and such are within the package tree and importable as modules, this flag can be specified which will add the additional __init__.py files in the version location and the environment location.
Fixed bug where rendering of comment text for table-level comments within .Operations.create_table_comment and .Operations.drop_table_comment was not properly quote-escaped within rendered Python code for autogenerate.
Modified the logic of the .Rewriter object such that it keeps a memoization of which directives it has processed, so that it can ensure it processes a particular directive only once, and additionally fixed .Rewriter so that it functions correctly for multiple-pass autogenerate schemes, such as the one illustrated in the "multidb" template. By tracking which directives have been processed, a multiple-pass scheme which calls upon the .Rewriter multiple times for the same structure as elements are added can work without running duplicate operations on the same elements more than once.
Alembic 1.1 bumps the minimum version of SQLAlchemy to 1.1. As was the case before, Python requirements remain at Python 2.7, or in the 3.x series Python 3.4.
The test suite for Alembic now makes use of SQLAlchemy's testing framework directly. Previously, Alembic had its own version of this framework that was mostly copied from that of SQLAlchemy to enable testing with older SQLAlchemy versions. The majority of this code is now removed so that both projects can leverage improvements from a common testing framework.
Fixed bug where the double-percent logic applied to some dialects such as psycopg2 would be rendered in --sql mode, by allowing dialect options to be passed through to the dialect used to generate SQL and then providing paramstyle="named" so that percent signs need not be doubled. For users having this issue, existing env.py scripts need to add dialect_opts={"paramstyle": "named"} to their offline context.configure(). See the alembic/templates/generic/env.py template for an example.
Fixed use of the deprecated "imp" module, which is used to detect pep3147 availability as well as to locate .pyc files, which started emitting deprecation warnings during the test suite. The warnings were not being emitted earlier during the test suite, the change is possibly due to changes in py.test itself but this is not clear. The check for pep3147 is set to True for any Python version 3.5 or greater now and importlib is used when available. Note that some dependencies such as distutils may still be emitting this warning. Tests are adjusted to accommodate for dependencies that emit the warning as well.
Fixed issue where emitting a change of column name for MySQL did not preserve the column comment, even if it were specified as existing_comment.
Removed the "python setup.py test" feature in favor of a straight run of "tox". Per Pypa / pytest developers, "setup.py" commands are in general headed towards deprecation in favor of tox. The tox.ini script has been updated such that running "tox" with no arguments will perform a single run of the test suite against the default installed Python interpreter.
The "alembic init" command will now proceed if the target directory exists as long as it's still empty. Previously, it would not proceed if the directory existed. The new behavior is modeled from what git does, to accommodate for container or other deployments where an Alembic target directory may need to be already mounted instead of being created with alembic init. Pull request courtesy Aviskar KC.
SQLite server default reflection will ensure parenthesis are surrounding a column default expression that is detected as being a non-constant expression, such as a datetime() default, to accommodate for the requirement that SQL expressions have to be parenthesized when being sent as DDL. Parenthesis are not added to constant expressions to allow for maximum cross-compatibility with other dialects and existing test suites (such as Alembic's), which necessarily entails scanning the expression to eliminate for constant numeric and string values. The logic is added to the two "reflection->DDL round trip" paths which are currently autogenerate and batch migration. Within autogenerate, the logic is on the rendering side, whereas in batch the logic is installed as a column reflection hook.
Improved SQLite server default comparison to accommodate for a text() construct that added parenthesis directly vs. a construct that relied upon the SQLAlchemy SQLite dialect to render the parenthesis, as well as improved support for various forms of constant expressions such as values that are quoted vs. non-quoted.
Fixed bug where the "literal_binds" flag was not being set when autogenerate would create a server default value, meaning server default comparisons would fail for functions that contained literal values.
Added support for MySQL "DROP CHECK", which is added as of MySQL 8.0.16, separate from MariaDB's "DROP CONSTRAINT" for CHECK constraints. The MySQL Alembic implementation now checks for "MariaDB" in server_version_info to decide which one to use.
Fixed issue where MySQL databases need to use CHANGE COLUMN when altering a server default of CURRENT_TIMESTAMP, NOW() and probably other functions that are only usable with DATETIME/TIMESTAMP columns. While MariaDB supports both CHANGE and ALTER COLUMN in this case, MySQL databases only support CHANGE. So the new logic is that if the server default change is against a DateTime-oriented column, the CHANGE format is used unconditionally, as in the vast majority of cases the server default is to be CURRENT_TIMESTAMP which may also be potentially bundled with an "ON UPDATE CURRENT_TIMESTAMP" directive, which SQLAlchemy does not currently support as a distinct field. The fix additionally improves the server default comparison logic when the "ON UPDATE" clause is present and there are parenthesis to be adjusted for as is the case on some MariaDB versions.
Warnings emitted by Alembic now include a default stack level of 2, and in some cases it's set to 3, in order to help warnings indicate more closely where they are originating from. Pull request courtesy Ash Berlin-Taylor.
Replaced the Python compatibility routines for getargspec() with a fully vendored version based on getfullargspec() from Python 3.3. Originally, Python was emitting deprecation warnings for this function in Python 3.8 alphas. While this change was reverted, it was observed that Python 3 implementations for getfullargspec() are an order of magnitude slower as of the 3.4 series where it was rewritten against Signature. While Python plans to improve upon this situation, SQLAlchemy projects for now are using a simple replacement to avoid any future issues.
Fixed bug introduced in release 0.9.0 where the helptext for commands inadvertently got expanded to include function docstrings from the command.py module. The logic has been adjusted to only refer to the first line(s) preceding the first line break within each docstring, as was the original intent.
Added an assertion in .RevisionMap.get_revisions and other methods which ensures revision numbers are passed as strings or collections of strings. Driver issues particularly on MySQL may inadvertently be passing bytes here which leads to failures later on.
Fixed bug when using the .EnvironmentContext.configure.compare_server_default flag set to True where a server default that is introduced in the table metadata on an Integer column, where there is no existing server default in the database, would raise a TypeError.
Simplified the internal scheme used to generate the alembic.op namespace to no longer attempt to generate full method signatures (e.g. rather than generic *args, **kw) as this was not working in most cases anyway, while in rare circumstances it would in fact sporadically have access to the real argument names and then fail when generating the function due to missing symbols in the argument signature.
Removed use of deprecated force parameter for SQLAlchemy quoting functions as this parameter will be removed in a future release. Pull request courtesy Parth Shandilya(ParthS007).
Fixed issue where server default comparison on the PostgreSQL dialect would fail for a blank string on Python 3.7 only, due to a change in regular expression behavior in Python 3.7.
Fixed issue in new comment support where autogenerated Python code for comments wasn't using repr() thus causing issues with quoting. Pull request courtesy Damien Garaud.
Added Table and Column level comments for supported backends. New methods .Operations.create_table_comment and .Operations.drop_table_comment are added. A new arguments .Operations.alter_column.comment and .Operations.alter_column.existing_comment are added to .Operations.alter_column. Autogenerate support is also added to ensure comment add/drops from tables and columns are generated as well as that .Operations.create_table, .Operations.add_column both include the comment field from the source .Table or .Column object.
Resolved remaining Python 3 deprecation warnings, covering the use of inspect.formatargspec() with a vendored version copied from the Python standard library, importing collections.abc above Python 3.3 when testing against abstract base classes, fixed one occurrence of log.warn(), as well as a few invalid escape sequences.
Code hosting has been moved to GitHub, at https://github.com/sqlalchemy/alembic. Additionally, the main Alembic website documentation URL is now https://alembic.sqlalchemy.org.
Fixed regression caused by 513, where the logic to consume mssql_include was not correctly interpreting the case where the flag was not present, breaking the op.create_index directive for SQL Server as a whole.
The system=True flag on .Column, used primarily in conjunction with the Postgresql "xmin" column, now renders within the autogenerate render process, allowing the column to be excluded from DDL. Additionally, adding a system=True column to a model will produce no autogenerate diff as this column is implicitly present in the database.
Fixed issue where usage of the SQL Server mssql_include option within a .Operations.create_index would raise a KeyError, as the additional column(s) need to be added to the table object used by the construct internally.
Fixed an issue where revision descriptions were essentially being formatted twice. Any revision description that contained characters like %, writing output to stdout will fail because the call to config.print_stdout attempted to format any additional args passed to the function. This fix now only applies string formatting if any args are provided along with the output text.
Fixed issue where removed method union_update() was used when a customized .MigrationScript instance included entries in the .imports data member, raising an AttributeError.
For Alembic 1.0, Python 2.6 / 3.3 support is being dropped, allowing a fixed setup.py to be built as well as universal wheels. Pull request courtesy Hugo.
With the 1.0 release, Alembic's minimum SQLAlchemy support version moves to 0.9.0, previously 0.7.9.
Fixed issue in batch where dropping a primary key column, then adding it back under the same name but without the primary_key flag, would not remove it from the existing PrimaryKeyConstraint. If a new PrimaryKeyConstraint is added, it is used as-is, as was the case before.
The "op.drop_constraint()" directive will now render using repr() for the schema name, in the same way that "schema" renders for all the other op directives. Pull request courtesy Denis Kataev.
Added basic capabilities for external dialects to support rendering of "nested" types, like arrays, in a manner similar to that of the Postgresql dialect.
Fixed issue where "autoincrement=True" would not render for a column that specified it, since as of SQLAlchemy 1.1 this is no longer the default value for "autoincrement". Note the behavior only takes effect against the SQLAlchemy 1.1.0 and higher; for pre-1.1 SQLAlchemy, "autoincrement=True" does not render as was the case before. Pull request courtesy Elad Almos.
Added new flag --indicate-current to the alembic history command. When listing versions, it will include the token "(current)" to indicate the given version is a current head in the target database. Pull request courtesy Kazutaka Mise.
The fix for 455 in version 0.9.6 involving MySQL server default comparison was entirely non functional, as the test itself was also broken and didn't reveal that it wasn't working. The regular expression to compare server default values like CURRENT_TIMESTAMP to current_timestamp() is repaired.
Fixed bug where MySQL server default comparisons were basically not working at all due to incorrect regexp added in 455. Also accommodates for MariaDB 10.2 quoting differences in reporting integer based server defaults.
Fixed bug in op.drop_constraint() for MySQL where quoting rules would not be applied to the constraint name.
Fixed bug where the .Script.as_revision_number method did not accommodate for the 'heads' identifier, which in turn caused the .EnvironmentContext.get_head_revisions and .EnvironmentContext.get_revision_argument methods to be not usable when multiple heads were present. The :meth:.EnvironmentContext.get_head_revisions method returns a tuple in all cases as documented.
Fixed bug where autogenerate of .ExcludeConstraint would render a raw quoted name for a Column that has case-sensitive characters, which when invoked as an inline member of the Table would produce a stack trace that the quoted name is not found. An incoming Column object is now rendered as sa.column('name').
Fixed bug where the indexes would not be included in a migration that was dropping the owning table. The fix now will also emit DROP INDEX for the indexes ahead of time, but more importantly will include CREATE INDEX in the downgrade migration.
Fixed the autogenerate of the module prefix when rendering the text_type parameter of postgresql.HSTORE, in much the same way that we do for ARRAY's type and JSON's text_type.
Added support for DROP CONSTRAINT to the MySQL Alembic dialect to support MariaDB 10.2 which now has real CHECK constraints. Note this change does not add autogenerate support, only support for op.drop_constraint() to work.
Fixed regression caused by 421 which would cause case-sensitive quoting rules to interfere with the comparison logic for index names, thus causing indexes to show as added for indexes that have case-sensitive names. Works with SQLAlchemy 0.9 and later series.
Fixed bug where autogenerate would produce a DROP statement for the index implicitly created by a Postgresql EXCLUDE constraint, rather than skipping it as is the case for indexes implicitly generated by unique constraints. Makes use of SQLAlchemy 1.0.x's improved "duplicates index" metadata and requires at least SQLAlchemy version 1.0.x to function correctly.
Fixed a few Python3.6 deprecation warnings by replacing StopIteration with return, as well as using getfullargspec() instead of getargspec() under Python 3.
An addition to 441 fixed in 0.9.5, we forgot to also filter for the + sign in migration names which also breaks due to the relative migrations feature.
Fixed bug expanding upon the fix for 85 which adds the correct module import to the "inner" type for an ARRAY type, the fix now accommodates for the generic sqlalchemy.types.ARRAY type added in SQLAlchemy 1.1, rendering the inner type correctly regardless of whether or not the Postgresql dialect is present.
Fixed bug where server default comparison of CURRENT_TIMESTAMP would fail on MariaDB 10.2 due to a change in how the function is represented by the database during reflection.
Fixed bug where comparison of Numeric types would produce a difference if the Python-side Numeric inadvertently specified a non-None "scale" with a "precision" of None, even though this Numeric type will pass over the "scale" argument when rendering. Pull request courtesy Ivan Mmelnychuk.
The alembic history command will now make use of the revision environment env.py unconditionally if the revision_environment configuration flag is set to True. Previously, the environment would only be invoked if the history specification were against a database-stored revision token.
The name of the temporary table in batch mode is now generated off of the original table name itself, to avoid conflicts for the unusual case of multiple batch operations running against the same database schema at the same time.
A .ForeignKeyConstraint can now render correctly if the link_to_name flag is set, as it will not attempt to resolve the name from a "key" in this case. Additionally, the constraint will render as-is even if the remote column name isn't present on the referenced remote table.
Reworked "sourceless" system to be fully capable of handling any combination of: Python2/3x, pep3149 or not, PYTHONOPTIMIZE or not, for locating and loading both env.py files as well as versioning files. This includes: locating files inside of __pycache__ as well as listing out version files that might be only in versions/__pycache__, deduplicating version files that may be in versions/__pycache__ and versions/ at the same time, correctly looking for .pyc or .pyo files based on if pep488 is present or not. The latest Python3x deprecation warnings involving importlib are also corrected.
A .CommandError is raised if the "--rev-id" passed to the .revision command contains dashes or at-signs, as this interferes with the command notation used to locate revisions.
Added support for the dialect-specific keyword arguments to .Operations.drop_index. This includes support for postgresql_concurrently and others.
Fixed bug in timezone feature introduced in 425 when the creation date in a revision file is calculated, to accommodate for timezone names that contain mixed-case characters in their name as opposed to all uppercase. Pull request courtesy Nils Philippsen.
Added an additional attribute to the new .EnvironmentContext.configure.on_version_apply API, .MigrationInfo.up_revision_ids, to accommodate for the uncommon case of the alembic stamp command being used to move from multiple branches down to a common branchpoint; there will be multiple "up" revisions in this one case.
Added a new callback hook .EnvironmentContext.configure.on_version_apply, which allows user-defined code to be invoked each time an individual upgrade, downgrade, or stamp operation proceeds against a database. Pull request courtesy John Passaro.
433
Fixed bug where autogen comparison of a .Variant datatype would not compare to the dialect level type for the "default" implementation of the .Variant, returning the type as changed between database and table metadata.
431
Fixed unit tests to run correctly under the SQLAlchemy 1.0.x series prior to version 1.0.10 where a particular bug involving Postgresql exclude constraints was fixed.
429
Repaired .Operations.rename_table for SQL Server when the target table is in a remote schema, the schema name is omitted from the "new name" argument.
425
Added a new configuration option timezone, a string timezone name that will be applied to the create date timestamp rendered inside the revision file as made available to the file_template used to generate the revision filename. Note this change adds the python-dateutil package as a dependency.
421
The autogenerate compare scheme now takes into account the name truncation rules applied by SQLAlchemy's DDL compiler to the names of the .Index object, when these names are dynamically truncated due to a too-long identifier name. As the identifier truncation is deterministic, applying the same rule to the metadata name allows correct comparison to the database-derived name.
419
A warning is emitted when an object that's not a ~sqlalchemy.engine.Connection is passed to .EnvironmentContext.configure. For the case of a ~sqlalchemy.engine.Engine passed, the check for "in transaction" introduced in version 0.9.0 has been relaxed to work in the case of an attribute error, as some users appear to be passing an ~sqlalchemy.engine.Engine and not a ~sqlalchemy.engine.Connection.
417
An adjustment to the bug fix for 369 to accommodate for env.py scripts that use an enclosing transaction distinct from the one that the context provides, so that the check for "didn't commit the transaction" doesn't trigger in this scenario.
38
The .EnvironmentContext.configure.target_metadata parameter may now be optionally specified as a sequence of .MetaData objects instead of a single .MetaData object. The autogenerate process will process the sequence of .MetaData objects in order.
369
A .CommandError is now raised when a migration file opens a database transaction and does not close/commit/rollback, when the backend database or environment options also specify transactional_ddl is False. When transactional_ddl is not in use, Alembic doesn't close any transaction so a transaction opened by a migration file will cause the following migrations to fail to apply.
413
The autoincrement=True flag is now rendered within the .Operations.alter_column operation if the source column indicates that this flag should be set to True. The behavior is sensitive to the SQLAlchemy version in place, as the "auto" default option is new in SQLAlchemy 1.1. When the source column indicates autoincrement as True or "auto", the flag will render as True if the original column contextually indicates that it should have "autoincrement" keywords, and when the source column explicitly sets it to False, this is also rendered. The behavior is intended to preserve the AUTO_INCREMENT flag on MySQL as the column is fully recreated on this backend. Note that this flag does not support alteration of a column's "autoincrement" status, as this is not portable across backends.
411
Fixed bug where Postgresql JSON/JSONB types rendered on SQLAlchemy 1.1 would render the "astext_type" argument which defaults to the Text() type without the module prefix, similarly to the issue with ARRAY fixed in 85.
85
Fixed bug where Postgresql ARRAY type would not render the import prefix for the inner type; additionally, user-defined renderers take place for the inner type as well as the outer type. Pull request courtesy Paul Brackin.
process_revision_directives_command
Added a keyword argument process_revision_directives to the .command.revision API call. This function acts in the same role as the environment-level .EnvironmentContext.configure.process_revision_directives, and allows API use of the command to drop in an ad-hoc directive process function. This function can be used among other things to place a complete .MigrationScript structure in place.
412
Added support for Postgresql EXCLUDE constraints, including the operation directive .Operations.create_exclude_constraints as well as autogenerate render support for the ExcludeConstraint object as present in a Table. Autogenerate detection for an EXCLUDE constraint added or removed to/from an existing table is not implemented as the SQLAlchemy Postgresql dialect does not yet support reflection of EXCLUDE constraints.
Additionally, unknown constraint types now warn when encountered within an autogenerate action rather than raise.
fk_schema_compare
Fixed bug in .ops.create_foreign_key where the internal table representation would not be created properly if the foreign key referred to a table in a different schema of the same name. Pull request courtesy Konstantin Lebedev.
406
The alembic_version table, when initially created, now establishes a primary key constraint on the "version_num" column, to suit database engines that don't support tables without primary keys. This behavior can be controlled using the parameter .EnvironmentContext.configure.version_table_pk. Note that this change only applies to the initial creation of the alembic_version table; it does not impact any existing alembic_version table already present.
402
Fixed bug where doing batch_op.drop_constraint() against the primary key constraint would fail to remove the "primary_key" flag from the column, resulting in the constraint being recreated.
update_uq_dedupe
Adjusted the logic originally added for 276 that detects MySQL unique constraints which are actually unique indexes to be generalized for any dialect that has this behavior, for SQLAlchemy version 1.0 and greater. This is to allow for upcoming SQLAlchemy support for unique constraint reflection for Oracle, which also has no dedicated concept of "unique constraint" and instead establishes a unique index.
356
Added a file ignore for Python files of the form .#<name>.py, which are generated by the Emacs editor. Pull request courtesy Markus Mattes.
393
Adjustment to the "please adjust!" comment in the script.py.mako template so that the generated comment starts with a single pound sign, appeasing flake8.
Batch mode will not use CAST() to copy data if type_ is given, however the basic type affinity matches that of the existing type. This to avoid SQLite's CAST of TIMESTAMP which results in truncation of the data, in those cases where the user needs to add redundant type_ for other reasons.
Continued pep8 improvements by adding appropriate whitespace in the base template for generated migrations. Pull request courtesy Markus Mattes.
Added an additional check when reading in revision files to detect if the same file is being read twice; this can occur if the same directory or a symlink equivalent is present more than once in version_locations. A warning is now emitted and the file is skipped. Pull request courtesy Jiri Kuncar.
Fixed bug where usage of a custom TypeDecorator which returns a per-dialect type via .TypeDecorator.load_dialect_impl that differs significantly from the default "impl" for the type decorator would fail to compare correctly during autogenerate.
Fixed bug in Postgresql "functional index skip" behavior where a functional index that ended in ASC/DESC wouldn't be detected as something we can't compare in autogenerate, leading to duplicate definitions in autogenerated files.
Fixed bug where the "base" specifier, as in "base:head", could not be used explicitly when --sql mode was present.
The imports in the default script.py.mako are now at the top so that flake8 editors don't complain by default. PR courtesy Guilherme Mansur.
Added support for the USING clause to the ALTER COLUMN operation for Postgresql. Support is via the .op.alter_column.postgresql_using parameter. Pull request courtesy Frazer McLean.
Autogenerate with type comparison enabled will pick up on the timezone setting changing between DateTime types. Pull request courtesy David Szotten.
Fixed bug where upgrading to the head of a branch which is already present would fail, only if that head were also the dependency of a different branch that is also upgraded, as the revision system would see this as trying to go in the wrong direction. The check here has been refined to distinguish between same-branch revisions out of order vs. movement along sibling branches.
Adjusted the version traversal on downgrade such that we can downgrade to a version that is a dependency for a version in a different branch, without needing to remove that dependent version as well. Previously, the target version would be seen as a "merge point" for it's normal up-revision as well as the dependency. This integrates with the changes for 377 and 378 to improve treatment of branches with dependencies overall.
Fixed bug where a downgrade to a version that is also a dependency to a different branch would fail, as the system attempted to treat this as an "unmerge" of a merge point, when in fact it doesn't have the other side of the merge point available for update.
Fixed bug where the "alembic current" command wouldn't show a revision as a current head if it were also a dependency of a version in a different branch that's also applied. Extra logic is added to extract "implied" versions of different branches from the top-level versions listed in the alembic_version table.
Fixed bug where a repr() or str() of a Script object would fail if the script had multiple dependencies.
Fixed bug in autogen where if the DB connection sends the default schema as "None", this "None" would be removed from the list of schemas to check if include_schemas were set. This could possibly impact using include_schemas with SQLite.
Small adjustment made to the batch handling for reflected CHECK constraints to accommodate for SQLAlchemy 1.1 now reflecting these. Batch mode still does not support CHECK constraints from the reflected table as these can't be easily differentiated from the ones created by types such as Boolean.
Errors which occur within the Mako render step are now intercepted and raised as CommandErrors like other failure cases; the Mako exception itself is written using template-line formatting to a temporary file which is named in the exception message.
Added a fix to Postgresql server default comparison which first checks if the text of the default is identical to the original, before attempting to actually run the default. This accommodates for default-generation functions that generate a new value each time such as a uuid function.
Fixed bug introduced by the fix for 338 in version 0.8.4 where a server default could no longer be dropped in batch mode. Pull request courtesy Martin Domke.
Fixed bug where SQL Server arguments for drop_column() would not be propagated when running under a batch block. Pull request courtesy Michal Petrucha.
Fixed bug where the columns rendered in a PrimaryKeyConstraint in autogenerate would inappropriately render the "key" of the column, not the name. Pull request courtesy Jesse Dhillon.
Repaired batch migration support for "schema" types which generate constraints, in particular the Boolean datatype which generates a CHECK constraint. Previously, an alter column operation with this type would fail to correctly accommodate for the CHECK constraint on change both from and to this type. In the former case the operation would fail entirely, in the latter, the CHECK constraint would not get generated. Both of these issues are repaired.
Changing a schema type such as Boolean to a non-schema type would emit a drop constraint operation which emits NotImplementedError for the MySQL dialect. This drop constraint operation is now skipped when the constraint originates from a schema type.
A major improvement to the hash id generation function, which for some reason used an awkward arithmetic formula against uuid4() that produced values that tended to start with the digits 1-4. Replaced with a simple substring approach which provides an even distribution. Pull request courtesy Antti Haapala.
Added an autogenerate renderer for the .ExecuteSQLOp operation object; only renders if given a plain SQL string, otherwise raises NotImplementedError. Can be of help with custom autogenerate sequences that includes straight SQL execution. Pull request courtesy Jacob Magnusson.
Batch mode generates a FOREIGN KEY constraint that is self-referential using the ultimate table name, rather than _alembic_batch_temp. When the table is renamed from _alembic_batch_temp back to the original name, the FK now points to the right name. This will not work if referential integrity is being enforced (eg. SQLite "PRAGMA FOREIGN_KEYS=ON") since the original table is dropped and the new table then renamed to that name, however this is now consistent with how foreign key constraints on other tables already operate with batch mode; these don't support batch mode if referential integrity is enabled in any case.
Added a type-level comparator that distinguishes .Integer, .BigInteger, and .SmallInteger types and dialect-specific types; these all have "Integer" affinity so previously all compared as the same.
Fixed bug where the server_default parameter of alter_column() would not function correctly in batch mode.
Adjusted the rendering for index expressions such that a .Column object present in the source .Index will not be rendered as table-qualified; e.g. the column name will be rendered alone. Table-qualified names here were failing on systems such as Postgresql.
Fixed an 0.8 regression whereby the "imports" dictionary member of the autogen context was removed; this collection is documented in the "render custom type" documentation as a place to add new imports. The member is now known as .AutogenContext.imports and the documentation is repaired.
Fixed bug in batch mode where a table that had pre-existing indexes would create the same index on the new table with the same name, which on SQLite produces a naming conflict as index names are in a global namespace on that backend. Batch mode now defers the production of both existing and new indexes until after the entire table transfer operation is complete, which also means those indexes no longer take effect during the INSERT from SELECT section as well; the indexes are applied in a single step afterwards.
Added "pytest-xdist" as a tox dependency, so that the -n flag in the test command works if this is not already installed. Pull request courtesy Julien Danjou.
Fixed issue in PG server default comparison where model-side defaults configured with Python unicode literals would leak the "u" character from a repr() into the SQL used for comparison, creating an invalid SQL expression, as the server-side comparison feature in PG currently repurposes the autogenerate Python rendering feature to get a quoted version of a plain string default.
Added workaround in new foreign key option detection feature for MySQL's consideration of the "RESTRICT" option being the default, for which no value is reported from the database; the MySQL impl now corrects for when the model reports RESTRICT but the database reports nothing. A similar rule is in the default FK comparison to accommodate for the default "NO ACTION" setting being present in the model but not necessarily reported by the database, or vice versa.
A custom .EnvironmentContext.configure.process_revision_directives hook can now generate op directives within the .UpgradeOps and .DowngradeOps containers that will be generated as Python code even when the --autogenerate flag is False; provided that revision_environment=True, the full render operation will be run even in "offline" mode.
Repaired the render operation for the .ops.AlterColumnOp object to succeed when the "existing_type" field was not present.
Fixed a regression 0.8 whereby the "multidb" environment template failed to produce independent migration script segments for the output template. This was due to the reorganization of the script rendering system for 0.8. To accommodate this change, the .MigrationScript structure will in the case of multiple calls to .MigrationContext.run_migrations produce lists for the .MigrationScript.upgrade_ops and .MigrationScript.downgrade_ops attributes; each .UpgradeOps and .DowngradeOps instance keeps track of its own upgrade_token and downgrade_token, and each are rendered individually.
autogen_customizing_multiengine_revision - additional detail on the workings of the .EnvironmentContext.configure.process_revision_directives parameter when multiple calls to .MigrationContext.run_migrations are made.
Implemented support for autogenerate detection of changes in the ondelete, onupdate, initially and deferrable attributes of .ForeignKeyConstraint objects on SQLAlchemy backends that support these on reflection (as of SQLAlchemy 1.0.8 currently Postgresql for all four, MySQL for ondelete and onupdate only). A constraint object that modifies these values will be reported as a "diff" and come out as a drop/create of the constraint with the modified values. The fields are ignored for backends which don't reflect these attributes (as of SQLA 1.0.8 this includes SQLite, Oracle, SQL Server, others).
Fixed bug in batch mode where the batch_op.create_foreign_key() directive would be incorrectly rendered with the source table and schema names in the argument list.
Added new command alembic edit. This command takes the same arguments as alembic show, however runs the target script file within $EDITOR. Makes use of the python-editor library in order to facilitate the handling of $EDITOR with reasonable default behaviors across platforms. Pull request courtesy Michel Albert.
Added new multiple-capable argument --depends-on to the alembic revision command, allowing depends_on to be established at the command line level rather than having to edit the file after the fact. depends_on identifiers may also be specified as branch names at the command line or directly within the migration file. The values may be specified as partial revision numbers from the command line which will be resolved to full revision numbers in the output file.
A range of positional argument names have been changed to be clearer and more consistent across methods within the .Operations namespace. The most prevalent form of name change is that the descriptive names constraint_name and table_name are now used where previously the name name would be used. This is in support of the newly modularized and extensible system of operation objects in alembic.operations.ops. An argument translation layer is in place across the alembic.op namespace that will ensure that named argument calling styles that use the old names will continue to function by transparently translating to the new names, also emitting a warning. This, along with the fact that these arguments are positional in any case and aren't normally passed with an explicit name, should ensure that the overwhelming majority of applications should be unaffected by this change. The only applications that are impacted are those that:
- use the
.Operationsobject directly in some way, rather than calling upon thealembic.opnamespace, and - invoke the methods on
.Operationsusing named keyword arguments for positional arguments liketable_name,constraint_name, etc., which commonly were namednameas of 0.7.6. - any application that is using named keyword arguments in place of positional argument for the recently added
.BatchOperationsobject may also be affected.
The naming changes are documented as "versionchanged" for 0.8.0:
.BatchOperations.create_check_constraint.BatchOperations.create_foreign_key.BatchOperations.create_index.BatchOperations.create_unique_constraint.BatchOperations.drop_constraint.BatchOperations.drop_index.Operations.create_check_constraint.Operations.create_foreign_key.Operations.create_primary_key.Operations.create_index.Operations.create_table.Operations.create_unique_constraint.Operations.drop_constraint.Operations.drop_index.Operations.drop_table
The default test runner via "python setup.py test" is now py.test. nose still works via run_tests.py.
The internal system for Alembic operations has been reworked to now build upon an extensible system of operation objects. New operations can be added to the op. namespace, including that they are available in custom autogenerate schemes.
operation_plugins
The internal system for autogenerate been reworked to build upon the extensible system of operation objects present in 302. As part of this change, autogenerate now produces a full object graph representing a list of migration scripts to be written as well as operation objects that will render all the Python code within them; a new hook .EnvironmentContext.configure.process_revision_directives allows end-user code to fully customize what autogenerate will do, including not just full manipulation of the Python steps to take but also what file or files will be written and where. Additionally, autogenerate is now extensible as far as database objects compared and rendered into scripts; any new operation directive can also be registered into a series of hooks that allow custom database/model comparison functions to run as well as to render new operation directives into autogenerate scripts.
alembic.autogenerate.toplevel
Fixed bug where in the erroneous case that alembic_version contains duplicate revisions, some commands would fail to process the version history correctly and end up with a KeyError. The fix allows the versioning logic to proceed, however a clear error is emitted later when attempting to update the alembic_version table.
Fixed critical issue where a complex series of branches/merges would bog down the iteration algorithm working over redundant nodes for millions of cycles. An internal adjustment has been made so that duplicate nodes are skipped within this iteration.
Implemented support for .BatchOperations.create_primary_key and .BatchOperations.create_check_constraint. Additionally, table keyword arguments are copied from the original reflected table, such as the "mysql_engine" keyword argument.
The .MigrationContext.stamp method, added as part of the versioning refactor in 0.7 as a more granular version of .command.stamp, now includes the "create the alembic_version table if not present" step in the same way as the command version, which was previously omitted.
Fixed bug where foreign key options including "onupdate", "ondelete" would not render within the op.create_foreign_key() directive, even though they render within a full ForeignKeyConstraint directive.
Repaired warnings that occur when running unit tests against SQLAlchemy 1.0.5 or greater involving the "legacy_schema_aliasing" flag.
Fixed bug where the case of multiple mergepoints that all have the identical set of ancestor revisions would fail to be upgradable, producing an assertion failure. Merge points were previously assumed to always require at least an UPDATE in alembic_revision from one of the previous revs to the new one, however in this case, if one of the mergepoints has already been reached, the remaining mergepoints have no row to UPDATE therefore they must do an INSERT of their target version.
Added support for type comparison functions to be not just per environment, but also present on the custom types themselves, by supplying a method compare_against_backend. Added a new documentation section compare_types describing type comparison fully.
Added a new option .EnvironmentContext.configure.literal_binds, which will pass the literal_binds flag into the compilation of SQL constructs when using "offline" mode. This has the effect that SQL objects like inserts, updates, deletes as well as textual statements sent using text() will be compiled such that the dialect will attempt to render literal values "inline" automatically. Only a subset of types is typically supported; the .Operations.inline_literal construct remains as the construct used to force a specific literal representation of a value. The .EnvironmentContext.configure.literal_binds flag is added to the "offline" section of the env.py files generated in new environments.
Fully implemented the ~.Operations.batch_alter_table.copy_from parameter for batch mode, which previously was not functioning. This allows "batch mode" to be usable in conjunction with --sql.
Repaired support for the .BatchOperations.create_index directive, which was mis-named internally such that the operation within a batch context could not proceed. The create index operation will proceed as part of a larger "batch table recreate" operation only if ~.Operations.batch_alter_table.recreate is set to "always", or if the batch operation includes other instructions that require a table recreate.
The --autogenerate option is not valid when used in conjunction with "offline" mode, e.g. --sql. This now raises a CommandError, rather than failing more deeply later on. Pull request courtesy Johannes Erdfelt.
Fixed bug where the mssql DROP COLUMN directive failed to include modifiers such as "schema" when emitting the DDL.
Postgresql "functional" indexes are necessarily skipped from the autogenerate process, as the SQLAlchemy backend currently does not support reflection of these structures. A warning is emitted both from the SQLAlchemy backend as well as from the Alembic backend for Postgresql when such an index is detected.
Fixed bug where MySQL backend would report dropped unique indexes and/or constraints as both at the same time. This is because MySQL doesn't actually have a "unique constraint" construct that reports differently than a "unique index", so it is present in both lists. The net effect though is that the MySQL backend will report a dropped unique index/constraint as an index in cases where the object was first created as a unique constraint, if no other information is available to make the decision. This differs from other backends like Postgresql which can report on unique constraints and unique indexes separately.
Fixed bug where using a partial revision identifier as the "starting revision" in --sql mode in a downgrade operation would fail to resolve properly.
As a side effect of this change, the .EnvironmentContext.get_starting_revision_argument method will return the "starting" revision in its originally-given "partial" form in all cases, whereas previously when running within the .command.stamp command, it would have been resolved to a full number before passing it to the .EnvironmentContext. The resolution of this value to a real revision number has basically been moved to a more fundamental level within the offline migration process.
Added a new feature .Config.attributes, to help with the use case of sharing state such as engines and connections on the outside with a series of Alembic API calls; also added a new cookbook section to describe this simple but pretty important use case.
connection_sharing
The format of the default env.py script has been refined a bit; it now uses context managers not only for the scope of the transaction, but also for connectivity from the starting engine. The engine is also now called a "connectable" in support of the use case of an external connection being passed in.
Added support for "alembic stamp" to work when given "heads" as an argument, when multiple heads are present.
Repaired issue where a server default specified without text() that represented a numeric or floating point (e.g. with decimal places) value would fail in the Postgresql-specific check for "compare server default"; as PG accepts the value with quotes in the table specification, it's still valid. Pull request courtesy Dimitris Theodorou.
The rendering of a ~sqlalchemy.schema.ForeignKeyConstraint will now ensure that the names of the source and target columns are the database-side name of each column, and not the value of the .key attribute as may be set only on the Python side. This is because Alembic generates the DDL for constraints as standalone objects without the need to actually refer to an in-Python ~sqlalchemy.schema.Table object, so there's no step that would resolve these Python-only key names to database column names.
Fixed bug in foreign key autogenerate where if the in-Python table used custom column keys (e.g. using the key='foo' kwarg to Column), the comparison of existing foreign keys to those specified in the metadata would fail, as the reflected table would not have these keys available which to match up. Foreign key comparison for autogenerate now ensures it's looking at the database-side names of the columns in all cases; this matches the same functionality within unique constraints and indexes.
Fixed issue in autogenerate type rendering where types that belong to modules that have the name "sqlalchemy" in them would be mistaken as being part of the sqlalchemy. namespace. Pull req courtesy Bartosz Burclaf.
Fixed regression in new versioning system where upgrade / history operation would fail on AttributeError if no version files were present at all.
Adjusted the SQLite backend regarding autogen of unique constraints to work fully with the current SQLAlchemy 1.0, which now will report on UNIQUE constraints that have no name.
Fixed bug in batch where if the target table contained multiple foreign keys to the same target table, the batch mechanics would fail with a "table already exists" error. Thanks for the help on this from Lucas Kahlert.
Fixed an issue where the MySQL routine to skip foreign-key-implicit indexes would also catch unnamed unique indexes, as they would be named after the column and look like the FK indexes. Pull request courtesy Johannes Erdfelt.
Repaired a regression in both the MSSQL and Oracle dialects whereby the overridden _exec() method failed to return a value, as is needed now in the 0.7 series.
The render_as_batch flag was inadvertently hardcoded to True, so all autogenerates were spitting out batch mode...this has been fixed so that batch mode again is only when selected in env.py.
Support for autogenerate of FOREIGN KEY constraints has been added. These are delivered within the autogenerate process in the same manner as UNIQUE constraints, including include_object support. Big thanks to Ann Kamyshnikova for doing the heavy lifting here.
Added ~.Operations.batch_alter_table.naming_convention argument to .Operations.batch_alter_table, as this is necessary in order to drop foreign key constraints; these are often unnamed on the target database, and in the case that they are named, SQLAlchemy is as of the 0.9 series not including these names yet.
dropping_sqlite_foreign_keys
Fixed bug where the "source_schema" argument was not correctly passed when calling .BatchOperations.create_foreign_key. Pull request courtesy Malte Marquarding.
Repaired the inspection, copying and rendering of CHECK constraints and so-called "schema" types such as Boolean, Enum within the batch copy system; the CHECK constraint will not be "doubled" when the table is copied, and additionally the inspection of the CHECK constraint for its member columns will no longer fail with an attribute error.
Added two new arguments .Operations.batch_alter_table.reflect_args and .Operations.batch_alter_table.reflect_kwargs, so that arguments may be passed directly to suit the ~.sqlalchemy.schema.Table object that will be reflected.
batch_controlling_table_reflection
The "multiple heads / branches" feature has now landed. This is by far the most significant change Alembic has seen since its inception; while the workflow of most commands hasn't changed, and the format of version files and the alembic_version table are unchanged as well, a new suite of features opens up in the case where multiple version files refer to the same parent, or to the "base". Merging of branches, operating across distinct named heads, and multiple independent bases are now all supported. The feature incurs radical changes to the internals of versioning and traversal, and should be treated as "beta mode" for the next several subsequent releases within 0.7.
branches
In conjunction with support for multiple independent bases, the specific version directories are now also configurable to include multiple, user-defined directories. When multiple directories exist, the creation of a revision file with no down revision requires that the starting directory is indicated; the creation of subsequent revisions along that lineage will then automatically use that directory for new files.
multiple_version_directories
Added "move and copy" workflow, where a table to be altered is copied to a new one with the new structure and the old one dropped, is now implemented for SQLite as well as all database backends in general using the new .Operations.batch_alter_table system. This directive provides a table-specific operations context which gathers column- and constraint-level mutations specific to that table, and at the end of the context creates a new table combining the structure of the old one with the given changes, copies data from old table to new, and finally drops the old table, renaming the new one to the existing name. This is required for fully featured SQLite migrations, as SQLite has very little support for the traditional ALTER directive. The batch directive is intended to produce code that is still compatible with other databases, in that the "move and copy" process only occurs for SQLite by default, while still providing some level of sanity to SQLite's requirement by allowing multiple table mutation operations to proceed within one "move and copy" as well as providing explicit control over when this operation actually occurs. The "move and copy" feature may be optionally applied to other backends as well, however dealing with referential integrity constraints from other tables must still be handled explicitly.
batch_migrations
Relative revision identifiers as used with alembic upgrade, alembic downgrade and alembic history can be combined with specific revisions as well, e.g. alembic upgrade ae10+3, to produce a migration target relative to the given exact version.
The alembic revision command accepts the --sql option to suit some very obscure use case where the revision_environment flag is set up, so that env.py is run when alembic revision is run even though autogenerate isn't specified. As this flag is otherwise confusing, error messages are now raised if alembic revision is invoked with both --sql and --autogenerate or with --sql without revision_environment being set.
Added a rule for Postgresql to not render a "drop unique" and "drop index" given the same name; for now it is assumed that the "index" is the implicit one PostgreSQL generates. Future integration with new SQLAlchemy 1.0 features will improve this to be more resilient.
A change in the ordering when columns and constraints are dropped; autogenerate will now place the "drop constraint" calls before the "drop column" calls, so that columns involved in those constraints still exist when the constraint is dropped.
New commands added: alembic show, alembic heads and alembic merge. Also, a new option --verbose has been added to several informational commands, such as alembic history, alembic current, alembic branches, and alembic heads. alembic revision also contains several new options used within the new branch management system. The output of commands has been altered in many cases to support new fields and attributes; the history command in particular now returns it's "verbose" output only if --verbose is sent; without this flag it reverts to it's older behavior of short line items (which was never changed in the docs).
The --head_only option to the alembic current command is deprecated; the current command now lists just the version numbers alone by default; use --verbose to get at additional output.
Added new argument .Config.config_args, allows a dictionary of replacement variables to be passed which will serve as substitution values when an API-produced .Config consumes the .ini file. Pull request courtesy Noufal Ibrahim.
The Oracle dialect sets "transactional DDL" to False by default, as Oracle does not support transactional DDL.
Fixed a variety of issues surrounding rendering of Python code that contains unicode literals. The first is that the "quoted_name" construct that SQLAlchemy uses to represent table and column names as well as schema names does not repr() correctly on Py2K when the value contains unicode characters; therefore an explicit stringification is added to these. Additionally, SQL expressions such as server defaults were not being generated in a unicode-safe fashion leading to decode errors if server defaults contained non-ascii characters.
The .Operations.add_column directive will now additionally emit the appropriate CREATE INDEX statement if the ~sqlalchemy.schema.Column object specifies index=True. Pull request courtesy David Szotten.
The ~sqlalchemy.schema.Table object is now returned when the .Operations.create_table method is used. This Table is suitable for use in subsequent SQL operations, in particular the .Operations.bulk_insert operation.
Indexes and unique constraints are now included in the .EnvironmentContext.configure.include_object hook. Indexes are sent with type "index" and unique constraints with type "unique_constraint".
Bound parameters are now resolved as "literal" values within the SQL expression inside of a CheckConstraint(), when rendering the SQL as a text string; supported for SQLAlchemy 0.8.0 and forward.
Added a workaround for SQLAlchemy issue #3023 (fixed in 0.9.5) where a column that's part of an explicit PrimaryKeyConstraint would not have its "nullable" flag set to False, thus producing a false autogenerate. Also added a related correction to MySQL which will correct for MySQL's implicit server default of '0' when a NULL integer column is turned into a primary key column.
Repaired issue related to the fix for #208 and others; a composite foreign key reported by MySQL would cause a KeyError as Alembic attempted to remove MySQL's implicitly generated indexes from the autogenerate list.
If the "alembic_version" table is present in the target metadata, autogenerate will skip this also. Pull request courtesy Dj Gilcrease.
The .EnvironmentContext.configure.version_table and .EnvironmentContext.configure.version_table_schema arguments are now honored during the autogenerate process, such that these names will be used as the "skip" names on both the database reflection and target metadata sides.
The default value of the .EnvironmentContext.configure.user_module_prefix parameter is no longer the same as the SQLAlchemy prefix. When omitted, user-defined types will now use the __module__ attribute of the type class itself when rendering in an autogenerated module.
Revision files are now written out using the 'wb' modifier to open(), since Mako reads the templates with 'rb', thus preventing CRs from being doubled up as has been observed on windows. The encoding of the output now defaults to 'utf-8', which can be configured using a newly added config file parameter output_encoding.
Added support for use of the ~sqlalchemy.sql.elements.quoted_name construct when using the schema argument within operations. This allows a name containing a dot to be fully quoted, as well as to provide configurable quoting on a per-name basis.
Added a routine by which the Postgresql Alembic dialect inspects the server default of INTEGER/BIGINT columns as they are reflected during autogenerate for the pattern nextval(<name>...) containing a potential sequence name, then queries pg_catalog to see if this sequence is "owned" by the column being reflected; if so, it assumes this is a SERIAL or BIGSERIAL column and the server default is omitted from the column reflection as well as any kind of server_default comparison or rendering, along with an INFO message in the logs indicating this has taken place. This allows SERIAL/BIGSERIAL columns to keep the SEQUENCE from being unnecessarily present within the autogenerate operation.
The system by which autogenerate renders expressions within a ~sqlalchemy.schema.Index, the server_default of ~sqlalchemy.schema.Column, and the existing_server_default of .Operations.alter_column has been overhauled to anticipate arbitrary SQLAlchemy SQL constructs, such as func.somefunction(), cast(), desc(), and others. The system does not, as might be preferred, render the full-blown Python expression as originally created within the application's source code, as this would be exceedingly complex and difficult. Instead, it renders the SQL expression against the target backend that's subject to the autogenerate, and then renders that SQL inside of a ~sqlalchemy.sql.expression.text construct as a literal SQL string. This approach still has the downside that the rendered SQL construct may not be backend-agnostic in all cases, so there is still a need for manual intervention in that small number of cases, but overall the majority of cases should work correctly now. Big thanks to Carlos Rivera for pull requests and support on this.
SQLAlchemy's testing infrastructure is now used to run tests. This system supports both nose and pytest and opens the way for Alembic testing to support any number of backends, parallel testing, and 3rd party dialect testing.
Minimum SQLAlchemy version is now 0.7.6, however at least 0.8.4 is strongly recommended. The overhaul of the test suite allows for fully passing tests on all SQLAlchemy versions from 0.7.6 on forward.
The "match" keyword is not sent to .ForeignKeyConstraint by .Operations.create_foreign_key when SQLAlchemy 0.7 is in use; this keyword was added to SQLAlchemy as of 0.8.0.
Fixed bug in MSSQL dialect where "rename table" wasn't using sp_rename() as is required on SQL Server. Pull request courtesy Łukasz Bołdys.
Added support for functional indexes when using the .Operations.create_index directive. Within the list of columns, the SQLAlchemy text() construct can be sent, embedding a literal SQL expression; the .Operations.create_index will perform some hackery behind the scenes to get the .Index construct to cooperate. This works around some current limitations in .Index which should be resolved on the SQLAlchemy side at some point.
A file named __init__.py in the versions/ directory is now ignored by Alembic when the collection of version files is retrieved. Pull request courtesy Michael Floering.
Fixed Py3K bug where an attempt would be made to sort None against string values when autogenerate would detect tables across multiple schemas, including the default schema. Pull request courtesy paradoxxxzero.
Autogenerate render will render the arguments within a Table construct using *[...] when the number of columns/elements is greater than 255. Pull request courtesy Ryan P. Kelly.
Fixed bug where foreign key constraints would fail to render in autogenerate when a schema name was present. Pull request courtesy Andreas Zeidler.
Some deep-in-the-weeds fixes to try to get "server default" comparison working better across platforms and expressions, in particular on the Postgresql backend, mostly dealing with quoting/not quoting of various expressions at the appropriate time and on a per-backend basis. Repaired and tested support for such defaults as Postgresql interval and array defaults.
When a run of Alembic command line fails due to CommandError, the output now prefixes the string with "FAILED:", and the error is also written to the log output using log.error().
Liberalized even more the check for MySQL indexes that shouldn't be counted in autogenerate as "drops"; this time it's been reported that an implicitly created index might be named the same as a composite foreign key constraint, and not the actual columns, so we now skip those when detected as well.
Added a new accessor .MigrationContext.config, when used in conjunction with a .EnvironmentContext and .Config, this config will be returned. Patch courtesy Marc Abramowitz.
This releases' "autogenerate index detection" bug, when a MySQL table includes an Index with the same name as a column, autogenerate reported it as an "add" even though its not; this is because we ignore reflected indexes of this nature due to MySQL creating them implicitly. Indexes that are named the same as a column are now ignored on MySQL if we see that the backend is reporting that it already exists; this indicates that we can still detect additions of these indexes but not drops, as we cannot distinguish a backend index same-named as the column as one that is user generated or mysql-generated.
Added new feature .EnvironmentContext.configure.transaction_per_migration, which when True causes the BEGIN/COMMIT pair to incur for each migration individually, rather than for the whole series of migrations. This is to assist with some database directives that need to be within individual transactions, without the need to disable transactional DDL entirely.
Fixed bug where the include_object() filter would not receive the original .Column object when evaluating a database-only column to be dropped; the object would not include the parent .Table nor other aspects of the column that are important for generating the "downgrade" case where the column is recreated.
Fixed bug where .EnvironmentContext.get_x_argument would fail if the .Config in use didn't actually originate from a command line call.
Fixed another bug regarding naming conventions, continuing from 183, where add_index() drop_index() directives would not correctly render the f() construct when the index contained a convention-driven name.
Added quoting to the table name when the special EXEC is run to drop any existing server defaults or constraints when the .Operations.drop_column.mssql_drop_check or .Operations.drop_column.mssql_drop_default arguments are used.
Added/fixed support for MySQL "SET DEFAULT" / "DROP DEFAULT" phrases, which will now be rendered if only the server default is changing or being dropped (e.g. specify None to alter_column() to indicate "DROP DEFAULT"). Also added support for rendering MODIFY rather than CHANGE when the column name isn't changing.
Added support for the initially, match keyword arguments as well as dialect-specific keyword arguments to .Operations.create_foreign_key.
- tags
feature
- tickets
163
Altered the support for "sourceless" migration files (e.g. only .pyc or .pyo present) so that the flag "sourceless=true" needs to be in alembic.ini for this behavior to take effect.
The feature that keeps on giving, index/unique constraint autogenerate detection, has even more fixes, this time to accommodate database dialects that both don't yet report on unique constraints, but the backend does report unique constraints as indexes. The logic Alembic uses to distinguish between "this is an index!" vs. "this is a unique constraint that is also reported as an index!" has now been further enhanced to not produce unwanted migrations when the dialect is observed to not yet implement get_unique_constraints() (e.g. mssql). Note that such a backend will no longer report index drops for unique indexes, as these cannot be distinguished from an unreported unique index.
Extensive changes have been made to more fully support SQLAlchemy's new naming conventions feature. Note that while SQLAlchemy has added this feature as of 0.9.2, some additional fixes in 0.9.4 are needed to resolve some of the issues:
- The
.Operationsobject now takes into account the naming conventions that are present on the.MetaDataobject that's associated using~.EnvironmentContext.configure.target_metadata. When.Operationsrenders a constraint directive likeADD CONSTRAINT, it now will make use of this naming convention when it produces its own temporary.MetaDataobject. - Note however that the autogenerate feature in most cases generates constraints like foreign keys and unique constraints with the final names intact; the only exception are the constraints implicit with a schema-type like Boolean or Enum. In most of these cases, the naming convention feature will not take effect for these constraints and will instead use the given name as is, with one exception....
- Naming conventions which use the
"%(constraint_name)s"token, that is, produce a new name that uses the original name as a component, will still be pulled into the naming convention converter and be converted. The problem arises when autogenerate renders a constraint with it's already-generated name present in the migration file's source code, the name will be doubled up at render time due to the combination of #1 and #2. So to work around this, autogenerate now renders these already-tokenized names using the new.Operations.fcomponent. This component is only generated if SQLAlchemy 0.9.4 or greater is in use.
Therefore it is highly recommended that an upgrade to Alembic 0.6.4 be accompanied by an upgrade of SQLAlchemy 0.9.4, if the new naming conventions feature is used.
autogen_naming_conventions
Suppressed IOErrors which can raise when program output pipe is closed under a program like head; however this only works on Python 2. On Python 3, there is not yet a known way to suppress the BrokenPipeError warnings without prematurely terminating the program via signals.
Fixed bug where .Operations.bulk_insert would not function properly when .Operations.inline_literal values were used, either in --sql or non-sql mode. The values will now render directly in --sql mode. For compatibility with "online" mode, a new flag ~.Operations.bulk_insert.multiinsert can be set to False which will cause each parameter set to be compiled and executed with individual INSERT statements.
Fixed a failure of the system that allows "legacy keyword arguments" to be understood, which arose as of a change in Python 3.4 regarding decorators. A workaround is applied that allows the code to work across Python 3 versions.
The .command.revision command now returns the .Script object corresponding to the newly generated revision. From this structure, one can get the revision id, the module documentation, and everything else, for use in scripts that call upon this command. Pull request courtesy Robbie Coomber.
Added a workaround for when we call fcntl.ioctl() to get at TERMWIDTH; if the function returns zero, as is reported to occur in some pseudo-ttys, the message wrapping system is disabled in the same way as if ioctl() failed.
Added new argument .EnvironmentContext.configure.user_module_prefix. This prefix is applied when autogenerate renders a user-defined type, which here is defined as any type that is from a module outside of the sqlalchemy. hierarchy. This prefix defaults to None, in which case the .EnvironmentContext.configure.sqlalchemy_module_prefix is used, thus preserving the current behavior.
Added support for autogenerate covering the use case where .Table objects specified in the metadata have an explicit schema attribute whose name matches that of the connection's default schema (e.g. "public" for Postgresql). Previously, it was assumed that "schema" was None when it matched the "default" schema, now the comparison adjusts for this.
The .compare_metadata public API function now takes into account the settings for .EnvironmentContext.configure.include_object, .EnvironmentContext.configure.include_symbol, and .EnvironmentContext.configure.include_schemas, in the same way that the --autogenerate command does. Pull request courtesy Roman Podoliaka.
Calling .bulk_insert with an empty list will not emit any commands on the current connection. This was already the case with --sql mode, so is now the case with "online" mode.
Enabled schema support for index and unique constraint autodetection; previously these were non-functional and could in some cases lead to attribute errors. Pull request courtesy Dimitris Theodorou.
More fixes to index autodetection; indexes created with expressions like DESC or functional indexes will no longer cause AttributeError exceptions when attempting to compare the columns.
The .ScriptDirectory system that loads migration files from a versions/ directory now supports so-called "sourceless" operation, where the .py files are not present and instead .pyc or .pyo files are directly present where the .py files should be. Note that while Python 3.3 has a new system of locating .pyc/.pyo files within a directory called __pycache__ (e.g. PEP-3147), PEP-3147 maintains support for the "source-less imports" use case, where the .pyc/.pyo are in present in the "old" location, e.g. next to the .py file; this is the usage that's supported even when running Python3.3.
Autogenerate for op.create_table() will not include a PrimaryKeyConstraint() that has no columns.
Fixed bug in the not-internally-used .ScriptDirectory.get_base method which would fail if called on an empty versions directory.
An almost-rewrite of the new unique constraint/index autogenerate detection, to accommodate a variety of issues. The emphasis is on not generating false positives for those cases where no net change is present, as these errors are the ones that impact all autogenerate runs:
- Fixed an issue with unique constraint autogenerate detection where a named
UniqueConstrainton both sides with column changes would render with the "add" operation before the "drop", requiring the user to reverse the order manually.- Corrected for MySQL's apparent addition of an implicit index for a foreign key column, so that it doesn't show up as "removed". This required that the index/constraint autogen system query the dialect-specific implementation for special exceptions.
- reworked the "dedupe" logic to accommodate MySQL's bi-directional duplication of unique indexes as unique constraints, and unique constraints as unique indexes. Postgresql's slightly different logic of duplicating unique constraints into unique indexes continues to be accommodated as well. Note that a unique index or unique constraint removal on a backend that duplicates these may show up as a distinct "remove_constraint()" / "remove_index()" pair, which may need to be corrected in the post-autogenerate if multiple backends are being supported.
- added another dialect-specific exception to the SQLite backend when dealing with unnamed unique constraints, as the backend can't currently report on constraints that were made with this technique, hence they'd come out as "added" on every run.
- the
op.create_table()directive will be auto-generated with theUniqueConstraintobjects inline, but will not double them up with a separatecreate_unique_constraint()call, which may have been occurring. Indexes still get rendered as distinctop.create_index()calls even when the corresponding table was created in the same script.- the inline
UniqueConstraintwithinop.create_table()includes all the options likedeferrable,initially, etc. Previously these weren't rendering.
Added new argument mssql_drop_foreign_key to .Operations.drop_column. Like mssql_drop_default and mssql_drop_check, will do an inline lookup for a single foreign key which applies to this column, and drop it. For a column with more than one FK, you'd still need to explicitly use .Operations.drop_constraint given the name, even though only MSSQL has this limitation in the first place.
The MSSQL backend will add the batch separator (e.g. "GO") in --sql mode after the final COMMIT statement, to ensure that statement is also processed in batch mode. Courtesy Derek Harland.
Fixed bug where .op.alter_column in the MySQL dialect would fail to apply quotes to column names that had mixed casing or spaces.
Expanded the size of the "slug" generated by "revision" to 40 characters, which is also configurable by new field truncate_slug_length; and also split on the word rather than the character; courtesy Frozenball.
Fixed the output wrapping for Alembic message output, so that we either get the terminal width for "pretty printing" with indentation, or if not we just output the text as is; in any case the text won't be wrapped too short.
Fixes to Py3k in-place compatibility regarding output encoding and related; the use of the new io.* package introduced some incompatibilities on Py2k. These should be resolved, due to the introduction of new adapter types for translating from io.* to Py2k file types, StringIO types. Thanks to Javier Santacruz for help with this.
Fixed py3k bug where the wrong form of next() was being called when using the list_templates command. Courtesy Chris Wilkes.
Support for autogeneration detection and rendering of indexes and unique constraints has been added. The logic goes through some effort in order to differentiate between true unique constraints and unique indexes, where there are some quirks on backends like Postgresql. The effort here in producing the feature and tests is courtesy of IJL.
Fixed bug introduced by new include_object argument where the inspected column would be misinterpreted when using a user-defined type comparison function, causing a KeyError or similar expression-related error. Fix courtesy Maarten van Schaik.
Added the "deferrable" keyword argument to .op.create_foreign_key so that DEFERRABLE constraint generation is supported; courtesy Pedro Romano.
Ensured that strings going to stdout go through an encode/decode phase, so that any non-ASCII characters get to the output stream correctly in both Py2k and Py3k. Also added source encoding detection using Mako's parse_encoding() routine in Py2k so that the __doc__ of a non-ascii revision file can be treated as unicode in Py2k.
Added new kw argument to .EnvironmentContext.configure include_object. This is a more flexible version of the include_symbol argument which allows filtering of columns as well as tables from the autogenerate process, and in the future will also work for types, constraints and other constructs. The fully constructed schema object is passed, including its name and type as well as a flag indicating if the object is from the local application metadata or is reflected.
The output of the alembic history command is now expanded to show information about each change on multiple lines, including the full top message, resembling the formatting of git log.
Added alembic.config.Config.cmd_opts attribute, allows access to the argparse options passed to the alembic runner.
Added new command line argument -x, allows extra arguments to be appended to the command line which can be consumed within an env.py script by looking at context.config.cmd_opts.x, or more simply a new method .EnvironmentContext.get_x_argument.
Added support for options like "name" etc. to be rendered within CHECK constraints in autogenerate. Courtesy Sok Ann Yap.
Source repository has been moved from Mercurial to Git.
Repaired autogenerate rendering of ForeignKeyConstraint to include use_alter argument, if present.
Added -r argument to alembic history command, allows specification of [start]:[end] to view a slice of history. Accepts revision numbers, symbols "base", "head", a new symbol "current" representing the current migration, as well as relative ranges for one side at a time (i.e. -r-5:head, -rcurrent:+3). Courtesy Atsushi Odagiri for this feature.
Source base is now in-place for Python 2.6 through 3.3, without the need for 2to3. Support for Python 2.5 and below has been dropped. Huge thanks to Hong Minhee for all the effort on this!
Note
Alembic 0.5.0 now requires at least version 0.7.3 of SQLAlchemy to run properly. Support for 0.6 has been dropped.
Added version_table_schema argument to .EnvironmentContext.configure, complements the version_table argument to set an optional remote schema for the version table. Courtesy Christian Blume.
Fixed format of RENAME for table that includes schema with Postgresql; the schema name shouldn't be in the "TO" field.
Added output_encoding option to .EnvironmentContext.configure, used with --sql mode to apply an encoding to the output stream.
Added .Operations.create_primary_key operation, will generate an ADD CONSTRAINT for a primary key.
Fixed bug whereby double quoting would be applied to target column name during an sp_rename operation.
transactional_ddl flag for SQLite, MySQL dialects set to False. MySQL doesn't support it, SQLite does but current pysqlite driver does not.
upgrade and downgrade commands will list the first line of the docstring out next to the version number. Courtesy Hong Minhee.
Added --head-only option to "alembic current", will print current version plus the symbol "(head)" if this version is the head or not. Courtesy Charles-Axel Dein.
Autogenerate will render additional table keyword arguments like "mysql_engine" and others within op.create_table().
The rendering of any construct during autogenerate can be customized, in particular to allow special rendering for user-defined column, constraint subclasses, using new render_item argument to .EnvironmentContext.configure.
Fixed bug whereby create_index() would include in the constraint columns that are added to all Table objects using events, externally to the generation of the constraint. This is the same issue that was fixed for unique constraints in version 0.3.2.
Worked around a backwards-incompatible regression in Python3.3 regarding argparse; running "alembic" with no arguments now yields an informative error in py3.3 as with all previous versions. Courtesy Andrey Antukh.
SQLAlchemy 0.6 is no longer supported by Alembic - minimum version is 0.7.3, full support is as of 0.7.9.
A host of argument name changes within migration operations for consistency. Keyword arguments will continue to work on the old name for backwards compatibility, however required positional arguments will not:
.Operations.alter_column-name->new_column_name- old name will work for backwards compatibility.
.Operations.create_index-tablename->table_name-argument is positional.
.Operations.drop_index-tablename->table_name- old name will work for backwards compatibility.
.Operations.drop_constraint-tablename->table_name-argument is positional.
.Operations.drop_constraint-type->type_- old name will work for backwards compatibility
Fixed bug where autogenerate would fail if a Column to be added to a table made use of the ".key" parameter.
The "implicit" constraint generated by a type such as Boolean or Enum will not generate an ALTER statement when run on SQlite, which does not support ALTER for the purpose of adding/removing constraints separate from the column def itself. While SQLite supports adding a CHECK constraint at the column level, SQLAlchemy would need modification to support this. A warning is emitted indicating this constraint cannot be added in this scenario.
Added a workaround to setup.py to prevent "NoneType" error from occurring when "setup.py test" is run.
Added an append_constraint() step to each condition within test_autogenerate:AutogenRenderTest.test_render_fk_constraint_kwarg if the SQLAlchemy version is less than 0.8, as ForeignKeyConstraint does not auto-append prior to 0.8.
Added a README.unittests with instructions for running the test suite fully.
Added support for autogenerate render of ForeignKeyConstraint options onupdate, ondelete, initially, and deferred.
Autogenerate will include "autoincrement=False" in the rendered table metadata if this flag was set to false on the source .Column object.
Explicit error message describing the case when downgrade --sql is used without specifying specific start/end versions.
Removed erroneous "emit_events" attribute from operations.create_table() documentation.
Fixed the minute component in file_template which returned the month part of the create date.
Support for tables in alternate schemas has been added fully to all operations, as well as to the autogenerate feature. When using autogenerate, specifying the flag include_schemas=True to Environment.configure() will also cause autogenerate to scan all schemas located by Inspector.get_schema_names(), which is supported by some (but not all) SQLAlchemy dialects including Postgresql. Enormous thanks to Bruno Binet for a huge effort in implementing as well as writing tests. .
The command line runner has been organized into a reusable CommandLine object, so that other front-ends can re-use the argument parsing built in.
Added "stdout" option to Config, provides control over where the "print" output of commands like "history", "init", "current" etc. are sent.
Fixed the "multidb" template which was badly out of date. It now generates revision files using the configuration to determine the different upgrade<xyz>() methods needed as well, instead of needing to hardcode these. Huge thanks to BryceLohr for doing the heavy lifting here.
Fixed the regexp that was checking for .py files in the version directory to allow any .py file through. Previously it was doing some kind of defensive checking, probably from some early notions of how this directory works, that was prohibiting various filename patterns such as those which begin with numbers.
Fixed MySQL rendering for server_default which didn't work if the server_default was a generated SQL expression. Courtesy Moriyoshi Koizumi.
Added support for alteration of MySQL columns that have AUTO_INCREMENT, as well as enabling this flag. Courtesy Moriyoshi Koizumi.
Added include_symbol option to EnvironmentContext.configure(), specifies a callable which will include/exclude tables in their entirety from the autogeneration process based on name.
Added year, month, day, hour, minute, second variables to file_template.
Added 'primary' to the list of constraint types recognized for MySQL drop_constraint().
Added --sql argument to the "revision" command, for the use case where the "revision_environment" config option is being used but SQL access isn't desired.
Repaired create_foreign_key() for self-referential foreign keys, which weren't working at all.
'alembic' command reports an informative error message when the configuration is missing the 'script_directory' key.
Fixes made to the constraints created/dropped alongside so-called "schema" types such as Boolean and Enum. The create/drop constraint logic does not kick in when using a dialect that doesn't use constraints for these types, such as postgresql, even when existing_type is specified to alter_column(). Additionally, the constraints are not affected if existing_type is passed but type_ is not, i.e. there's no net change in type.
Improved error message when specifying non-ordered revision identifiers to cover the case when the "higher" rev is None, improved message overall.
Fixed issue whereby reflected server defaults wouldn't be quoted correctly; uses repr() now.
Fixed issue whereby when autogenerate would render create_table() on the upgrade side for a table that has a Boolean type, an unnecessary CheckConstraint() would be generated.
Implemented SQL rendering for CheckConstraint() within autogenerate upgrade, including for literal SQL as well as SQL Expression Language expressions.
Fixed command-line bug introduced by the "revision_environment" feature.
New config argument "revision_environment=true", causes env.py to be run unconditionally when the "revision" command is run, to support script.py.mako templates with dependencies on custom "template_args".
Added "template_args" option to configure() so that an env.py can add additional arguments to the template context when running the "revision" command. This requires either --autogenerate or the configuration directive "revision_environment=true".
Added "type" argument to op.drop_constraint(), and implemented full constraint drop support for MySQL. CHECK and undefined raise an error. MySQL needs the constraint type in order to emit a DROP CONSTRAINT.
Added version_table argument to EnvironmentContext.configure(), allowing for the configuration of the version table name.
Added support for "relative" migration identifiers, i.e. "alembic upgrade +2", "alembic downgrade -1". Courtesy Atsushi Odagiri for this feature.
Fixed bug whereby directories inside of the template directories, such as __pycache__ on Pypy, would mistakenly be interpreted as files which are part of the template.
Basic support for Oracle added, courtesy shgoh.
Added support for UniqueConstraint in autogenerate, courtesy Atsushi Odagiri
Fixed support of schema-qualified ForeignKey target in column alter operations, courtesy Alexander Kolov.
Fixed bug whereby create_unique_constraint() would include in the constraint columns that are added to all Table objects using events, externally to the generation of the constraint.
bulk_insert() fixes:
- bulk_insert() operation was not working most likely since the 0.2 series when used with an engine.
- Repaired bulk_insert() to complete when used against a lower-case-t table and executing with only one set of parameters, working around SQLAlchemy bug #2461 in this regard.
- bulk_insert() uses "inline=True" so that phrases like RETURNING and such don't get invoked for single-row bulk inserts.
- bulk_insert() will check that you're passing a list of dictionaries in, raises TypeError if not detected.
The focus of 0.3 is to clean up and more fully document the public API of Alembic, including better accessors on the MigrationContext and ScriptDirectory objects. Methods that are not considered to be public on these objects have been underscored, and methods which should be public have been cleaned up and documented, including:
MigrationContext.get_current_revision() ScriptDirectory.iterate_revisions() ScriptDirectory.get_current_head() ScriptDirectory.get_heads() ScriptDirectory.get_base() ScriptDirectory.generate_revision()
Added a bit of autogenerate to the public API in the form of the function alembic.autogenerate.compare_metadata.
Informative error message when op.XYZ directives are invoked at module import time.
Fixed inappropriate direct call to util.err() and therefore sys.exit() when Config failed to locate the config file within library usage.
Autogenerate will emit CREATE TABLE and DROP TABLE directives according to foreign key dependency order.
implement 'tablename' parameter on drop_index() as this is needed by some backends.
Added execution_options parameter to op.execute(), will call execution_options() on the Connection before executing.
The immediate use case here is to allow access to the new no_parameters option in SQLAlchemy 0.7.6, which allows some DBAPIs (psycopg2, MySQLdb) to allow percent signs straight through without escaping, thus providing cross-compatible operation with DBAPI execution and static script generation.
setup.py won't install argparse if on Python 2.7/3.2
script_location can be interpreted by pkg_resources.resource_filename(), if it is a non-absolute URI that contains colons. This scheme is the same one used by Pyramid.
added missing support for onupdate/ondelete flags for ForeignKeyConstraint, courtesy Giacomo Bagnoli
fixed a regression regarding an autogenerate error message, as well as various glitches in the Pylons sample template. The Pylons sample template requires that you tell it where to get the Engine from now. courtesy Marcin Kuzminski
drop_index() ensures a dummy column is added when it calls "Index", as SQLAlchemy 0.7.6 will warn on index with no column names.
Fixed the generation of CHECK constraint, regression from 0.2.0
API rearrangement allows everything Alembic does to be represented by contextual objects, including EnvironmentContext, MigrationContext, and Operations. Other libraries and applications can now use things like "alembic.op" without relying upon global configuration variables. The rearrangement was done such that existing migrations should be OK, as long as they use the pattern of "from alembic import context" and "from alembic import op", as these are now contextual objects, not modules.
The naming of revision files can now be customized to be some combination of "rev id" and "slug", the latter of which is based on the revision message. By default, the pattern "<rev>_<slug>" is used for new files. New script files should include the "revision" variable for this to work, which is part of the newer script.py.mako scripts.
env.py templates call connection.close() to better support programmatic usage of commands; use NullPool in conjunction with create_engine() as well so that no connection resources remain afterwards.
fix the config.main() function to honor the arguments passed, remove no longer used "scripts/alembic" as setuptools creates this for us.
Fixed alteration of column type on MSSQL to not include the keyword "TYPE".
Can create alembic.config.Config with no filename, use set_main_option() to add values. Also added set_section_option() which will add sections.
Clean up file write operations so that file handles are closed.
PyPy is supported.
Python 2.5 is supported, needs __future__.with_statement
Fix autogenerate so that "pass" is generated between the two comments if no net migrations were present.
Fix autogenerate bug that prevented correct reflection of a foreign-key referenced table in the list of "to remove".
Fix bug where create_table() didn't handle self-referential foreign key correctly
Default prefix for autogenerate directives is "op.", matching the mako templates.
Add alembic_module_prefix argument to configure() to complement sqlalchemy_module_prefix.
fix quotes not being rendered in ForeignKeConstraint during autogenerate
Initial release. Status of features:
Alembic is used in at least one production environment, but should still be considered ALPHA LEVEL SOFTWARE as of this release, particularly in that many features are expected to be missing / unimplemented. Major API changes are not anticipated but for the moment nothing should be assumed.
The author asks that you please report all issues, missing features, workarounds etc. to the bugtracker.
Python 3 is supported and has been tested.
The "Pylons" and "MultiDB" environment templates have not been directly tested - these should be considered to be samples to be modified as needed. Multiple database support itself is well tested, however.
Postgresql and MS SQL Server environments have been tested for several weeks in a production environment. In particular, some involved workarounds were implemented to allow fully-automated dropping of default- or constraint-holding columns with SQL Server.
MySQL support has also been implemented to a basic degree, including MySQL's awkward style of modifying columns being accommodated.
Other database environments not included among those three have not been tested, at all. This includes Firebird, Oracle, Sybase. Adding support for these backends should be straightforward. Please report all missing/ incorrect behaviors to the bugtracker! Patches are welcome here but are optional - please just indicate the exact format expected by the target database.
SQLite, as a backend, has almost no support for schema alterations to existing databases. The author would strongly recommend that SQLite not be used in a migration context - just dump your SQLite database into an intermediary format, then dump it back into a new schema. For dev environments, the dev installer should be building the whole DB from scratch. Or just use Postgresql, which is a much better database for non-trivial schemas. Requests for full ALTER support on SQLite should be reported to SQLite's bug tracker at http://www.sqlite.org/src/wiki?name=Bug+Reports, as Alembic will not be implementing the "rename the table to a temptable then copy the data into a new table" workaround. Note that Alembic will at some point offer an extensible API so that you can implement commands like this yourself.
Well-tested directives include add/drop table, add/drop column, including support for SQLAlchemy "schema" types which generate additional CHECK constraints, i.e. Boolean, Enum. Other directives not included here have not been strongly tested in production, i.e. rename table, etc.
Both "online" and "offline" migrations, the latter being generated SQL scripts to hand off to a DBA, have been strongly production tested against Postgresql and SQL Server.
Modify column type, default status, nullable, is functional and tested across PG, MSSQL, MySQL, but not yet widely tested in production usage.
Many migrations are still outright missing, i.e. create/add sequences, etc. As a workaround, execute() can be used for those which are missing, though posting of tickets for new features/missing behaviors is strongly encouraged.
Autogenerate feature is implemented and has been tested, though only a little bit in a production setting. In particular, detection of type and server default changes are optional and are off by default; they can also be customized by a callable. Both features work but can have surprises particularly the disparity between BIT/TINYINT and boolean, which hasn't yet been worked around, as well as format changes performed by the database on defaults when it reports back. When enabled, the PG dialect will execute the two defaults to be compared to see if they are equivalent. Other backends may need to do the same thing.
The autogenerate feature only generates "candidate" commands which must be hand-tailored in any case, so is still a useful feature and is safe to use. Please report missing/broken features of autogenerate! This will be a great feature and will also improve SQLAlchemy's reflection services.
Support for non-ASCII table, column and constraint names is mostly nonexistent. This is also a straightforward feature add as SQLAlchemy itself supports unicode identifiers; Alembic itself will likely need fixes to logging, column identification by key, etc. for full support here.