When a table or a column is renamed related indexes kept their name. This will lead to confusing names. This patch renames related indexes when a column or a table is renamed. Only indexes with names generated by rails will be renamed. Indexes with custom names will not be renamed.
Some adapter (SQLite3) need to perform renaming operations to support the rails DDL. These rename prefixes operate with prefixes. When an index name already uses up the full space provieded by `index_name_length` these internal operations will fail. This patch introduces `allowed_index_name_length` which respects the amount of characters used for internal operations. It will always be <= `index_name_length` and every adapter can define how many characters need to be reserved.
because of an ambiguous column name. This happened if the association model had a default scope that referenced a third table, and the third table also referenced the original table (with an identical foreign_key). Mysql requires that ambiguous columns are deambiguated by using the full table.column syntax. Postgresql and Sqlite use a different syntax for updates altogether (and don't tolerate table.name syntax), so the fix requires always including the full table.column and discarding it later for Sqlite and Postgresql.
…olumn reversible. [#8267]
When inserting new records, only the fields which have been changed from the defaults will actually be included in the INSERT statement. The other fields will be populated by the database. This is more efficient, and also means that it will be safe to remove database columns without getting subsequent errors in running app processes (so long as the code in those processes doesn't contain any references to the removed column).
This commit needs to be reverted because it introduces difficulties when using sqlite3 in development and other databases in production. This happens because when you create time column in sqlite3, it's dumped as datetime in schema.rb file. This reverts commit 57d534e, reversing changes made to 20f049f. Conflicts: activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
This is the 'top level' connection, inherited by any models that include ActiveRecord::Model or inherit from ActiveRecord::Base.