Update sqlalchemy to 1.3.7

[pyup-bot]

This PR updates sqlalchemy from 1.3.6 to 1.3.7.

Changelog

1.3.7

:released: August 14, 2019

 .. change::
     :tags: bug, sql
     :tickets: 4778

     Fixed issue where :class:`.Index` object which contained a mixture of
     functional expressions which were not resolvable to a particular column,
     in combination with string-based column names, would fail to initialize
     its internal state correctly leading to failures during DDL compilation.

 .. change::
     :tags: bug, sqlite
     :tickets: 4798

     The dialects that support json are supposed to take arguments
     ``json_serializer`` and ``json_deserializer`` at the create_engine() level,
     however the SQLite dialect calls them ``_json_serilizer`` and
     ``_json_deserilalizer``.  The names have been corrected, the old names are
     accepted with a change warning, and these parameters are now documented as
     :paramref:`.create_engine.json_serializer` and
     :paramref:`.create_engine.json_deserializer`.


 .. change::
     :tags: bug, mysql
     :tickets: 4804

     The MySQL dialects will emit "SET NAMES" at the start of a connection when
     charset is given to the MySQL driver, to appease an apparent behavior
     observed in MySQL 8.0 that raises a collation error when a UNION includes
     string columns unioned against columns of the form CAST(NULL AS CHAR(..)),
     which is what SQLAlchemy's polymorphic_union function does.   The issue
     seems to have affected PyMySQL for at least a year, however has recently
     appeared as of mysqlclient 1.4.4 based on changes in how this DBAPI creates
     a connection.  As the presence of this directive impacts three separate
     MySQL charset settings which each have intricate effects based on their
     presense,  SQLAlchemy will now emit the directive on new connections to
     ensure correct behavior.

 .. change::
     :tags: usecase, postgresql
     :tickets: 4623

     Added new dialect flag for the psycopg2 dialect, ``executemany_mode`` which
     supersedes the previous experimental ``use_batch_mode`` flag.
     ``executemany_mode`` supports both the "execute batch" and "execute values"
     functions provided by psycopg2, the latter which is used for compiled
     :func:`.insert` constructs.   Pull request courtesy Yuval Dinari.

     .. seealso::

         :ref:`psycopg2_executemany_mode`




 .. change::
     :tags: bug, sql
     :tickets: 4787

     Fixed bug where :meth:`.TypeEngine.column_expression` method would not be
     applied to subsequent SELECT statements inside of a UNION or other
     :class:`.CompoundSelect`, even though the SELECT statements are rendered at
     the topmost level of the statement.   New logic now differentiates between
     rendering the column expression, which is needed for all SELECTs in the
     list, vs. gathering the returned data type for the result row, which is
     needed only for the first SELECT.

 .. change:
     :tags: bug, sqlite
     :tickets: 4793

     Fixed bug where usage of "PRAGMA table_info" in SQLite dialect meant that
     reflection features to detect for table existence, list of table columns,
     and list of foreign keys, would default to any table in any attached
     database, when no schema name was given and the table did not exist in the
     base schema.  The fix explicitly runs PRAGMA for the 'main' schema and then
     the 'temp' schema if the 'main' returned no rows, to maintain the behavior
     of tables + temp tables in the "no schema" namespace, attached tables only
     in the "schema" namespace.


 .. change::
     :tags: bug, sql
     :tickets: 4780

     Fixed issue where internal cloning of SELECT constructs could lead to a key
     error if the copy of the SELECT changed its state such that its list of
     columns changed.  This was observed to be occurring in some ORM scenarios
     which may be unique to 1.3 and above, so is partially a regression fix.



 .. change::
     :tags: bug, orm
     :tickets: 4777

     Fixed regression caused by new selectinload for many-to-one logic where
     a primaryjoin condition not based on real foreign keys would cause
     KeyError if a related object did not exist for a given key value on the
     parent object.

 .. change::
     :tags: usecase, mysql
     :tickets: 4783

     Added reserved words ARRAY and MEMBER to the MySQL reserved words list, as
     MySQL 8.0 has now made these reserved.


 .. change::
     :tags: bug, events
     :tickets: 4794

     Fixed issue in event system where using the ``once=True`` flag with
     dynamically generated listener functions would cause event registration of
     future events to fail if those listener functions were garbage collected
     after they were used, due to an assumption that a listened function is
     strongly referenced.  The "once" wrapped is now modified to strongly
     reference the inner function persistently, and documentation is updated
     that using "once" does not imply automatic de-registration of listener
     functions.

 .. change::
     :tags: bug, mysql
     :tickets: 4751

     Added another fix for an upstream MySQL 8 issue where a case sensitive
     table name is reported incorrectly in foreign key constraint reflection,
     this is an extension of the fix first added for :ticket:`4344` which
     affects a case sensitive column name.  The new issue occurs through MySQL
     8.0.17, so the general logic of the 88718 fix remains in place.

     .. seealso::

         https://bugs.mysql.com/bug.php?id=96365 - upstream bug


 .. change::
     :tags: usecase, mssql
     :tickets: 4782

     Added new :func:`.mssql.try_cast` construct for SQL Server which emits
     "TRY_CAST" syntax.  Pull request courtesy Leonel Atencio.

 .. change::
     :tags: bug, orm
     :tickets: 4803

     Fixed bug where using :meth:`.Query.first` or a slice expression in
     conjunction with a query that has an expression based "offset" applied
     would raise TypeError, due to an "or" conditional against "offset" that did
     not expect it to be a SQL expression as opposed to an integer or None.


.. changelog::

Links

• PyPI: https://pypi.org/project/sqlalchemy
• Changelog: https://pyup.io/changelogs/sqlalchemy/
• Homepage: http://www.sqlalchemy.org