2.0.36

Released: October 15, 2024

orm

• [orm] [usecase] Added new parameter _orm.mapped_column.hash to ORM constructs such as _orm.mapped_column(), _orm.relationship(), etc., which is interpreted for ORM Native Dataclasses in the same way as other dataclass-specific field parameters.

  References: #11923

• [orm] [bug] Fixed bug in ORM bulk update/delete where using RETURNING with bulk update/delete in combination with populate_existing would fail to accommodate the populate_existing option.

  References: #11912

• [orm] [bug] Continuing from #11912, columns marked with mapped_column.onupdate, mapped_column.server_onupdate, or Computed are now refreshed in ORM instances when running an ORM enabled UPDATE with WHERE criteria, even if the statement does not use RETURNING or populate_existing.

  References: #11917

• [orm] [bug] Fixed regression caused by fixes to joined eager loading in #11449 released in 2.0.31, where a particular joinedload case could not be asserted correctly. We now have an example of that case so the assertion has been repaired to allow for it.

  References: #11965

• [orm] [bug] Improved the error message emitted when trying to map as dataclass a class while also manually providing the __table__ attribute. This usage is currently not supported.

  References: #11973

• [orm] [bug] Refined the check which the ORM lazy loader uses to detect "this would be loading by primary key and the primary key is NULL, skip loading" to take into account the current setting for the orm.Mapper.allow_partial_pks parameter. If this parameter is False, then a composite PK value that has partial NULL elements should also be skipped. This can apply to some composite overlapping foreign key configurations.

  References: #11995

• [orm] [bug] Fixed bug in ORM "update with WHERE clause" feature where an explicit .returning() would interfere with the "fetch" synchronize strategy due to an assumption that the ORM mapped class featured the primary key columns in a specific position within the RETURNING. This has been fixed to use appropriate ORM column targeting.

  References: #11997

sql

• [sql] [usecase] Datatypes that are binary based such as VARBINARY will resolve to LargeBinary when the TypeEngine.as_generic() method is called.

  References: #11978

• [sql] [bug] [regression] Fixed regression from 1.4 where some datatypes such as those derived from TypeDecorator could not be pickled when they were part of a larger SQL expression composition due to internal supporting structures themselves not being pickleable.

  References: #12002

schema

• [schema] [bug] Fixed bug where SQL functions passed to _schema.Column.server_default would not be rendered with the particular form of parenthesization now required by newer versions of MySQL and MariaDB. Pull request courtesy of huuya.

  References: #11317

postgresql

• [postgresql] [bug] [reflection] Fixed bug in reflection of table comments where unrelated text would be returned if an entry in the pg_description table happened to share the same oid (objoid) as the table being reflected.

  References: #11961

• [postgresql] [bug] The postgresql.JSON and postgresql.JSONB datatypes will now render a "bind cast" in all cases for all PostgreSQL backends, including psycopg2, whereas previously it was only enabled for some backends. This allows greater accuracy in allowing the database server to recognize when a string value is to be interpreted as JSON.

  References: #11994

mysql

• [mysql] [performance] Improved a query used for the MySQL 8 backend when reflecting foreign keys to be better optimized. Previously, for a database that had millions of columns across all tables, the query could be prohibitively slow; the query has been reworked to take better advantage of existing indexes.

  References: #11975