:released: January 9, 2025

.. change::

:tags: usecase, mariadb

:tickets: 10720

Added sql types ``INET4`` and ``INET6`` in the MariaDB dialect. Pull

request courtesy Adam Žurek.

.. change::

:tags: bug, orm

:tickets: 11370

Fixed issue regarding ``Union`` types that would be present in the

:paramref:`_orm.registry.type_annotation_map` of a :class:`_orm.registry`

or declarative base class, where a :class:`.Mapped` element that included

one of the subtypes present in that ``Union`` would be matched to that

entry, potentially ignoring other entries that matched exactly. The

correct behavior now takes place such that an entry should only match in

:paramref:`_orm.registry.type_annotation_map` exactly, as a ``Union`` type

is a self-contained type. For example, an attribute with ``Mapped[float]``

would previously match to a :paramref:`_orm.registry.type_annotation_map`

entry ``Union[float, Decimal]``; this will no longer match and will now

only match to an entry that states ``float``. Pull request courtesy Frazer

McLean.

.. change::

:tags: bug, postgresql

:tickets: 11724

Fixes issue in :meth:`.Dialect.get_multi_indexes` in the PostgreSQL

dialect, where an error would be thrown when attempting to use alembic with

a vector index from the pgvecto.rs extension.

.. change::

:tags: usecase, mysql, mariadb

:tickets: 11764

Added support for the ``LIMIT`` clause with ``DELETE`` for the MySQL and

MariaDB dialects, to complement the already present option for

``UPDATE``. The :meth:`.Delete.with_dialect_options` method of the

:func:`.delete` construct accepts parameters for ``mysql_limit`` and

``mariadb_limit``, allowing users to specify a limit on the number of rows

deleted. Pull request courtesy of Pablo Nicolás Estevez.

.. change::

:tags: bug, mysql, mariadb

Added logic to ensure that the ``mysql_limit`` and ``mariadb_limit``

parameters of :meth:`.Update.with_dialect_options` and

:meth:`.Delete.with_dialect_options` when compiled to string will only

compile if the parameter is passed as an integer; a ``ValueError`` is

raised otherwise.

.. change::

:tags: bug, orm

:tickets: 11944

Fixed bug in how type unions were handled within

:paramref:`_orm.registry.type_annotation_map` as well as

:class:`._orm.Mapped` that made the lookup behavior of ``a | b`` different

from that of ``Union[a, b]``.

.. change::

:tags: bug, orm

:tickets: 11955

Consistently handle ``TypeAliasType`` (defined in PEP 695) obtained with

the ``type X = int`` syntax introduced in python 3.12. Now in all cases one

such alias must be explicitly added to the type map for it to be usable

inside :class:`.Mapped`. This change also revises the approach added in

:ticket:`11305`, now requiring the ``TypeAliasType`` to be added to the

type map. Documentation on how unions and type alias types are handled by

SQLAlchemy has been added in the

:ref:`orm_declarative_mapped_column_type_map` section of the documentation.

.. change::

:tags: feature, oracle

:tickets: 12016

Added new table option ``oracle_tablespace`` to specify the ``TABLESPACE``

option when creating a table in Oracle. This allows users to define the

tablespace in which the table should be created. Pull request courtesy of

Miguel Grillo.

.. change::

:tags: orm, bug

:tickets: 12019

Fixed regression caused by an internal code change in response to recent

Mypy releases that caused the very unusual case of a list of ORM-mapped

attribute expressions passed to :meth:`.ColumnOperators.in_` to no longer

be accepted.

.. change::

:tags: oracle, usecase

:tickets: 12032

Use the connection attribute ``max_identifier_length`` available

in oracledb since version 2.5 when determining the identifier length

in the Oracle dialect.

.. change::

:tags: bug, sql

:tickets: 12084

Fixed issue in "lambda SQL" feature where the tracking of bound parameters

could be corrupted if the same lambda were evaluated across multiple

compile phases, including when using the same lambda across multiple engine

instances or with statement caching disabled.

.. change::

:tags: usecase, postgresql

:tickets: 12093

The :class:`_postgresql.Range` type now supports

:meth:`_postgresql.Range.__contains__`. Pull request courtesy of Frazer

McLean.

.. change::

:tags: bug, oracle

:tickets: 12100

Fixed compilation of ``TABLE`` function when used in a ``FROM`` clause in

Oracle Database dialect.

.. change::

:tags: bug, oracle

:tickets: 12150

Fixed issue in oracledb / cx_oracle dialects where output type handlers for

``CLOB`` were being routed to ``NVARCHAR`` rather than ``VARCHAR``, causing

a double conversion to take place.

.. change::

:tags: bug, postgresql

:tickets: 12170

Fixed issue where creating a table with a primary column of

:class:`_sql.SmallInteger` and using the asyncpg driver would result in

the type being compiled to ``SERIAL`` rather than ``SMALLSERIAL``.

.. change::

:tags: bug, orm

:tickets: 12207

Fixed issues in type handling within the

:paramref:`_orm.registry.type_annotation_map` feature which prevented the

use of unions, using either pep-604 or ``Union`` syntaxes under future

annotations mode, which contained multiple generic types as elements from

being correctly resolvable.

.. change::

:tags: bug, orm

:tickets: 12216

Fixed issue in event system which prevented an event listener from being

attached and detached from multiple class-like objects, namely the

:class:`.sessionmaker` or :class:`.scoped_session` targets that assign to

:class:`.Session` subclasses.

.. change::

:tags: bug, postgresql

:tickets: 12220

Adjusted the asyncpg dialect so that an empty SQL string, which is valid

for PostgreSQL server, may be successfully processed at the dialect level,

such as when using :meth:`.Connection.exec_driver_sql`. Pull request

courtesy Andrew Jackson.

.. change::

:tags: usecase, sqlite

:tickets: 7398

Added SQLite table option to enable ``STRICT`` tables. Pull request

courtesy of Guilherme Crocetti.