:released: September 16, 2024

 .. change::
     :tags: bug, orm, typing
     :tickets: 11820

     Fixed issue where it was not possible to use ``typing.Literal`` with
     ``Mapped[]`` on Python 3.8 and 3.9.  Pull request courtesy Frazer McLean.

 .. change::
     :tags: bug, sqlite, regression
     :tickets: 11840

     The changes made for SQLite CHECK constraint reflection in versions 2.0.33
     and 2.0.34 , :ticket:`11832` and :ticket:`11677`, have now been fully
     reverted, as users continued to identify existing use cases that stopped
     working after this change.   For the moment, because SQLite does not
     provide any consistent way of delivering information about CHECK
     constraints, SQLAlchemy is limited in what CHECK constraint syntaxes can be
     reflected, including that a CHECK constraint must be stated all on a
     single, independent line (or inline on a column definition)  without
     newlines, tabs in the constraint definition or unusual characters in the
     constraint name.  Overall, reflection for SQLite is tailored towards being
     able to reflect CREATE TABLE statements that were originally created by
     SQLAlchemy DDL constructs.  Long term work on a DDL parser that does not
     rely upon regular expressions may eventually improve upon this situation.
     A wide range of additional cross-dialect CHECK constraint reflection tests
     have been added as it was also a bug that these changes did not trip any
     existing tests.

 .. change::
     :tags: orm, bug
     :tickets: 11849

     Fixed issue in ORM evaluator where two datatypes being evaluated with the
     SQL concatenator operator would not be checked for
     :class:`.UnevaluatableError` based on their datatype; this missed the case
     of :class:`_postgresql.JSONB` values being used in a concatenate operation
     which is supported by PostgreSQL as well as how SQLAlchemy renders the SQL
     for this operation, but does not work at the Python level. By implementing
     :class:`.UnevaluatableError` for this combination, ORM update statements
     will now fall back to "expire" when a concatenated JSON value used in a SET
     clause is to be synchronized to a Python object.

 .. change::
     :tags: bug, orm
     :tickets: 11853

     An warning is emitted if :func:`_orm.joinedload` or
     :func:`_orm.subqueryload` are used as a top level option against a
     statement that is not a SELECT statement, such as with an
     ``insert().returning()``.   There are no JOINs in INSERT statements nor is
     there a "subquery" that can be repurposed for subquery eager loading, and
     for UPDATE/DELETE joinedload does not support these either, so it is never
     appropriate for this use to pass silently.

 .. change::
     :tags: bug, orm
     :tickets: 11855

     Fixed issue where using loader options such as :func:`_orm.selectinload`
     with additional criteria in combination with ORM DML such as
     :func:`_sql.insert` with RETURNING would not correctly set up internal
     contexts required for caching to work correctly, leading to incorrect
     results.

 .. change::
     :tags: bug, mysql
     :tickets: 11870

     Fixed issue in mariadbconnector dialect where query string arguments that
     weren't checked integer or boolean arguments would be ignored, such as
     string arguments like ``unix_socket``, etc.  As part of this change, the
     argument parsing for particular elements such as ``client_flags``,
     ``compress``, ``local_infile`` has been made more consistent across all
     MySQL / MariaDB dialect which accept each argument. Pull request courtesy
     Tobias Alex-Petersen.


.. changelog::

:released: September 4, 2024

 .. change::
     :tags: bug, orm
     :tickets: 11831

     Fixed regression caused by issue :ticket:`11814` which broke support for
     certain flavors of :pep:`593` ``Annotated`` in the type_annotation_map when
     builtin types such as ``list``, ``dict`` were used without an element type.
     While this is an incomplete style of typing, these types nonetheless
     previously would be located in the type_annotation_map correctly.

 .. change::
     :tags: bug, sqlite
     :tickets: 11832

     Fixed regression in SQLite reflection caused by :ticket:`11677` which
     interfered with reflection for CHECK constraints that were followed
     by other kinds of constraints within the same table definition.   Pull
     request courtesy Harutaka Kawamura.


.. changelog::

:released: September 3, 2024

 .. change::
     :tags: bug, sqlite
     :tickets: 11677

     Improvements to the regex used by the SQLite dialect to reflect the name
     and contents of a CHECK constraint.  Constraints with newline, tab, or
     space characters in either or both the constraint text and constraint name
     are now properly reflected.   Pull request courtesy Jeff Horemans.



 .. change::
     :tags: bug, engine
     :tickets: 11687

     Fixed issue in internal reflection cache where particular reflection
     scenarios regarding same-named quoted_name() constructs would not be
     correctly cached.  Pull request courtesy Felix Lüdin.

 .. change::
     :tags: bug, sql, regression
     :tickets: 11703

     Fixed regression in :meth:`_sql.Select.with_statement_hint` and others
     where the generative behavior of the method stopped producing a copy of the
     object.

 .. change::
     :tags: bug, mysql
     :tickets: 11731

     Fixed issue in MySQL dialect where using INSERT..FROM SELECT in combination
     with ON DUPLICATE KEY UPDATE would erroneously render on MySQL 8 and above
     the "AS new" clause, leading to syntax failures.  This clause is required
     on MySQL 8 to follow the VALUES clause if use of the "new" alias is
     present, however is not permitted to follow a FROM SELECT clause.


 .. change::
     :tags: bug, sqlite
     :tickets: 11746

     Improvements to the regex used by the SQLite dialect to reflect the name
     and contents of a UNIQUE constraint that is defined inline within a column
     definition inside of a SQLite CREATE TABLE statement, accommodating for tab
     characters present within the column / constraint line. Pull request
     courtesy John A Stevenson.




 .. change::
     :tags: bug, typing
     :tickets: 11782

     Fixed typing issue with :meth:`_sql.Select.with_only_columns`.

 .. change::
     :tags: bug, orm
     :tickets: 11788

     Correctly cleanup the internal top-level module registry when no
     inner modules or classes are registered into it.

 .. change::
     :tags: bug, schema
     :tickets: 11802

     Fixed bug where the ``metadata`` element of an ``Enum`` datatype would not
     be transferred to the new :class:`.MetaData` object when the type had been
     copied via a :meth:`.Table.to_metadata` operation, leading to inconsistent
     behaviors within create/drop sequences.

 .. change::
     :tags: bug, orm
     :tickets: 11814

     Improvements to the ORM annotated declarative type map lookup dealing with
     composed types such as ``dict[str, Any]`` linking to JSON (or others) with
     or without "future annotations" mode.



 .. change::
     :tags: change, general
     :tickets: 11818

     The pin for ``setuptools<69.3`` in ``pyproject.toml`` has been removed.
     This pin was to prevent a sudden change in setuptools to use :pep:`625`
     from taking place, which would change the file name of SQLAlchemy's source
     distribution on pypi to be an all lower case name, which is likely to cause
     problems with various build environments that expected the previous naming
     style.  However, the presence of this pin is holding back environments that
     otherwise want to use a newer setuptools, so we've decided to move forward
     with this change, with the assumption that build environments will have
     largely accommodated the setuptools change by now.



 .. change::
     :tags: bug, postgresql
     :tickets: 11821

     Revising the asyncpg ``terminate()`` fix first made in :ticket:`10717`
     which improved the resiliency of this call under all circumstances, adding
     ``asyncio.CancelledError`` to the list of exceptions that are intercepted
     as failing for a graceful ``.close()`` which will then proceed to call
     ``.terminate()``.

 .. change::
     :tags: bug, mssql
     :tickets: 11822

     Added error "The server failed to resume the transaction" to the list of
     error strings for the pymssql driver in determining a disconnect scenario,
     as observed by one user using pymssql under otherwise unknown conditions as
     leaving an unusable connection in the connection pool which fails to ping
     cleanly.

 .. change::
     :tags: bug, tests

     Added missing ``array_type`` property to the testing suite
     ``SuiteRequirements`` class.

.. changelog::

:released: August 5, 2024

 .. change::
     :tags: bug, examples
     :tickets: 10267

     Fixed issue in history_meta example where the "version" column in the
     versioned table needs to default to the most recent version number in the
     history table on INSERT, to suit the use case of a table where rows are
     deleted, and can then be replaced by new rows that re-use the same primary
     key identity.  This fix adds an additonal SELECT query per INSERT in the
     main table, which may be inefficient; for cases where primary keys are not
     re-used, the default function may be omitted.  Patch courtesy  Philipp H.
     v. Loewenfeld.

 .. change::
     :tags: bug, oracle
     :tickets: 11557

     Fixed table reflection on Oracle 10.2 and older where compression options
     are not supported.

 .. change::
     :tags: oracle, usecase
     :tickets: 10820

     Added API support for server-side cursors for the oracledb async dialect,
     allowing use of the :meth:`_asyncio.AsyncConnection.stream` and similar
     stream methods.

 .. change::
     :tags: bug, orm
     :tickets: 10834

     Fixed issue where using the :meth:`_orm.Query.enable_eagerloads` and
     :meth:`_orm.Query.yield_per` methods at the same time, in order to disable
     eager loading that's configured on the mapper directly, would be silently
     ignored, leading to errors or unexpected eager population of attributes.

 .. change::
     :tags: orm
     :tickets: 11163

     Added a warning noting when an
     :meth:`_engine.ConnectionEvents.engine_connect` event may be leaving
     a transaction open, which can alter the behavior of a
     :class:`_orm.Session` using such an engine as bind.
     On SQLAlchemy 2.1 :paramref:`_orm.Session.join_transaction_mode` will
     instead be ignored in all cases when the session bind is
     an :class:`_engine.Engine`.

 .. change::
     :tags: bug, general, regression
     :tickets: 11435

     Restored legacy class names removed from
     ``sqlalalchemy.orm.collections.*``, including
     :class:`_orm.MappedCollection`, :func:`_orm.mapped_collection`,
     :func:`_orm.column_mapped_collection`,
     :func:`_orm.attribute_mapped_collection`. Pull request courtesy Takashi
     Kajinami.

 .. change::
     :tags: bug, sql
     :tickets: 11471

     Follow up of :ticket:`11471` to fix caching issue where using the
     :meth:`.CompoundSelectState.add_cte` method of the
     :class:`.CompoundSelectState` construct would not set a correct cache key
     which distinguished between different CTE expressions. Also added tests
     that would detect issues similar to the one fixed in :ticket:`11544`.

 .. change::
     :tags: bug, mysql
     :tickets: 11479

     Fixed issue in MySQL dialect where ENUM values that contained percent signs
     were not properly escaped for the driver.


 .. change::
     :tags: usecase, oracle
     :tickets: 11480

     Implemented two-phase transactions for the oracledb dialect. Historically,
     this feature never worked with the cx_Oracle dialect, however recent
     improvements to the oracledb successor now allow this to be possible.  The
     two phase transaction API is available at the Core level via the
     :meth:`_engine.Connection.begin_twophase` method.

 .. change::
     :tags: bug, postgresql
     :tickets: 11522

     It is now considered a pool-invalidating disconnect event when psycopg2
     throws an "SSL SYSCALL error: Success" error message, which can occur when
     the SSL connection to Postgres is terminated abnormally.

 .. change::
     :tags: bug, schema
     :tickets: 11530

     Fixed additional issues in the event system triggered by unpickling of a
     :class:`.Enum` datatype, continuing from :ticket:`11365` and
     :ticket:`11360`,  where dynamically generated elements of the event
     structure would not be present when unpickling in a new process.

 .. change::
     :tags: bug, engine
     :tickets: 11532

     Fixed issue in "insertmanyvalues" feature where a particular call to
     ``cursor.fetchall()`` were not wrapped in SQLAlchemy's exception wrapper,
     which apparently can raise a database exception during fetch when using
     pyodbc.

 .. change::
     :tags: usecase, orm
     :tickets: 11575

     The :paramref:`_orm.aliased.name` parameter to :func:`_orm.aliased` may now
     be combined with the :paramref:`_orm.aliased.flat` parameter, producing
     per-table names based on a name-prefixed naming convention.  Pull request
     courtesy Eric Atkin.

 .. change::
     :tags: bug, postgresql
     :tickets: 11576

     Fixed issue where the :func:`_sql.collate` construct, which explicitly sets
     a collation for a given expression, would maintain collation settings for
     the underlying type object from the expression, causing SQL expressions to
     have both collations stated at once when used in further expressions for
     specific dialects that render explicit type casts, such as that of asyncpg.
     The :func:`_sql.collate` construct now assigns its own type to explicitly
     include the new collation, assuming it's a string type.

 .. change::
     :tags: bug, sql
     :tickets: 11592

     Fixed bug where the :meth:`.Operators.nulls_first()` and
     :meth:`.Operators.nulls_last()` modifiers would not be treated the same way
     as :meth:`.Operators.desc()` and :meth:`.Operators.asc()` when determining
     if an ORDER BY should be against a label name already in the statement. All
     four modifiers are now treated the same within ORDER BY.

 .. change::
     :tags: bug, orm, regression
     :tickets: 11625

     Fixed regression appearing in 2.0.21 caused by :ticket:`10279` where using
     a :func:`_sql.delete` or :func:`_sql.update` against an ORM class that is
     the base of an inheritance hierarchy, while also specifying that subclasses
     should be loaded polymorphically, would leak the polymorphic joins into the
     UPDATE or DELETE statement as well creating incorrect SQL.

 .. change::
     :tags: bug, orm, regression
     :tickets: 11661

     Fixed regression from version 1.4 in
     :meth:`_orm.Session.bulk_insert_mappings` where using the
     :paramref:`_orm.Session.bulk_insert_mappings.return_defaults` parameter
     would not populate the passed in dictionaries with newly generated primary
     key values.


 .. change::
     :tags: bug, oracle, sqlite
     :tickets: 11663

     Implemented bitwise operators for Oracle which was previously
     non-functional due to a non-standard syntax used by this database.
     Oracle's support for bitwise "or" and "xor" starts with server version 21.
     Additionally repaired the implementation of "xor" for SQLite.

     As part of this change, the dialect compliance test suite has been enhanced
     to include support for server-side bitwise tests; third party dialect
     authors should refer to new "supports_bitwise" methods in the
     requirements.py file to enable these tests.




 .. change::
     :tags: bug, typing

     Fixed internal typing issues to establish compatibility with mypy 1.11.0.
     Note that this does not include issues which have arisen with the
     deprecated mypy plugin used by SQLAlchemy 1.4-style code; see the addiional
     change note for this plugin indicating revised compatibility.

.. changelog::

:released: June 18, 2024

 .. change::
     :tags: usecase, reflection, mysql
     :tickets: 11285

     Added missing foreign key reflection option ``SET DEFAULT``
     in the MySQL and MariaDB dialects.
     Pull request courtesy of Quentin Roche.

 .. change::
     :tags: usecase, orm
     :tickets: 11361

     Added missing parameter :paramref:`_orm.with_polymorphic.name` that
     allows specifying the name of returned :class:`_orm.AliasedClass`.

 .. change::
     :tags: bug, orm
     :tickets: 11365

     Fixed issue where a :class:`.MetaData` collection would not be
     serializable, if an :class:`.Enum` or :class:`.Boolean` datatype were
     present which had been adapted. This specific scenario in turn could occur
     when using the :class:`.Enum` or :class:`.Boolean` within ORM Annotated
     Declarative form where type objects frequently get copied.

 .. change::
     :tags: schema, usecase
     :tickets: 11374

     Added :paramref:`_schema.Column.insert_default` as an alias of
     :paramref:`_schema.Column.default` for compatibility with
     :func:`_orm.mapped_column`.

 .. change::
     :tags: bug, general
     :tickets: 11417

     Set up full Python 3.13 support to the extent currently possible, repairing
     issues within internal language helpers as well as the serializer extension
     module.

 .. change::
     :tags: bug, sql
     :tickets: 11422

     Fixed issue when serializing an :func:`_sql.over` clause with
     unbounded range or rows.

 .. change::
     :tags: bug, sql
     :tickets: 11423

     Added missing methods :meth:`_sql.FunctionFilter.within_group`
     and :meth:`_sql.WithinGroup.filter`

 .. change::
     :tags: bug, sql
     :tickets: 11426

     Fixed bug in :meth:`_sql.FunctionFilter.filter` that would mutate
     the existing function in-place. It now behaves like the rest of the
     SQLAlchemy API, returning a new instance instead of mutating the
     original one.

 .. change::
     :tags: bug, orm
     :tickets: 11446

     Fixed issue where the :func:`_orm.selectinload` and
     :func:`_orm.subqueryload` loader options would fail to take effect when
     made against an inherited subclass that itself included a subclass-specific
     :paramref:`_orm.Mapper.with_polymorphic` setting.

 .. change::
     :tags: bug, orm
     :tickets: 11449

     Fixed very old issue involving the :paramref:`_orm.joinedload.innerjoin`
     parameter where making use of this parameter mixed into a query that also
     included joined eager loads along a self-referential or other cyclical
     relationship, along with complicating factors like inner joins added for
     secondary tables and such, would have the chance of splicing a particular
     inner join to the wrong part of the query.  Additional state has been added
     to the internal method that does this splice to make a better decision as
     to where splicing should proceed.

 .. change::
     :tags: bug, orm, regression
     :tickets: 11509

     Fixed bug in ORM Declarative where the ``__table__`` directive could not be
     declared as a class function with :func:`_orm.declared_attr` on a
     superclass, including an ``__abstract__`` class as well as coming from the
     declarative base itself.  This was a regression since 1.4 where this was
     working, and there were apparently no tests for this particular use case.

.. changelog::

:released: May 5, 2024

 .. change::
     :tags: bug, typing, regression
     :tickets: 11200

     Fixed typing regression caused by :ticket:`11055` in version 2.0.29 that
     added ``ParamSpec`` to the asyncio ``run_sync()`` methods, where using
     :meth:`_asyncio.AsyncConnection.run_sync` with
     :meth:`_schema.MetaData.reflect` would fail on mypy due to a mypy issue.
     Pull request courtesy of Francisco R. Del Roio.

 .. change::
     :tags: bug, engine
     :tickets: 11210

     Fixed issue in the
     :paramref:`_engine.Connection.execution_options.logging_token` option,
     where changing the value of ``logging_token`` on a connection that has
     already logged messages would not be updated to reflect the new logging
     token.  This in particular prevented the use of
     :meth:`_orm.Session.connection` to change the option on the connection,
     since the BEGIN logging message would already have been emitted.

 .. change::
     :tags: bug, orm
     :tickets: 11220

     Added new attribute :attr:`_orm.ORMExecuteState.is_from_statement` to
     detect statements created using :meth:`_sql.Select.from_statement`, and
     enhanced ``FromStatement`` to set :attr:`_orm.ORMExecuteState.is_select`,
     :attr:`_orm.ORMExecuteState.is_insert`,
     :attr:`_orm.ORMExecuteState.is_update`, and
     :attr:`_orm.ORMExecuteState.is_delete` according to the element that is
     sent to the :meth:`_sql.Select.from_statement` method itself.

 .. change::
     :tags: bug, test
     :tickets: 11268

     Ensure the ``PYTHONPATH`` variable is properly initialized when
     using ``subprocess.run`` in the tests.

 .. change::
     :tags: bug, orm
     :tickets: 11291

     Fixed issue in  :func:`_orm.selectin_polymorphic` loader option where
     attributes defined with :func:`_orm.composite` on a superclass would cause
     an internal exception on load.


 .. change::
     :tags: bug, orm, regression
     :tickets: 11292

     Fixed regression from 1.4 where using :func:`_orm.defaultload` in
     conjunction with a non-propagating loader like :func:`_orm.contains_eager`
     would nonetheless propagate the :func:`_orm.contains_eager` to a lazy load
     operation, causing incorrect queries as this option is only intended to
     come from an original load.



 .. change::
     :tags: bug, orm
     :tickets: 11305

     Fixed issue in ORM Annotated Declarative where typing issue where literals
     defined using :pep:`695` type aliases would not work with inference of
     :class:`.Enum` datatypes. Pull request courtesy of Alc-Alc.

 .. change::
     :tags: bug, engine
     :tickets: 11306

     Fixed issue in cursor handling which affected handling of duplicate
     :class:`_sql.Column` or similar objcts in the columns clause of
     :func:`_sql.select`, both in combination with arbitary :func:`_sql.text()`
     clauses in the SELECT list, as well as when attempting to retrieve
     :meth:`_engine.Result.mappings` for the object, which would lead to an
     internal error.



 .. change::
     :tags: bug, orm
     :tickets: 11327

     Fixed issue in :func:`_orm.selectin_polymorphic` loader option where the
     SELECT emitted would only accommodate for the child-most class among the
     result rows that were returned, leading intermediary-class attributes to be
     unloaded if there were no concrete instances of that intermediary-class
     present in the result.   This issue only presented itself for multi-level
     inheritance hierarchies.

 .. change::
     :tags: bug, orm
     :tickets: 11332

     Fixed issue in :meth:`_orm.Session.bulk_save_objects` where the form of the
     identity key produced when using ``return_defaults=True`` would be
     incorrect. This could lead to an errors during pickling as well as identity
     map mismatches.

 .. change::
     :tags: bug, installation
     :tickets: 11334

     Fixed an internal class that was testing for unexpected attributes to work
     correctly under upcoming Python 3.13.   Pull request courtesy Edgar
     Ramírez-Mondragón.

 .. change::
     :tags: bug, orm
     :tickets: 11347

     Fixed issue where attribute key names in :class:`_orm.Bundle` would not be
     correct when using ORM enabled :class:`_sql.select` vs.
     :class:`_orm.Query`, when the statement contained duplicate column names.

 .. change::
     :tags: bug, typing

     Fixed issue in typing for :class:`_orm.Bundle` where creating a nested
     :class:`_orm.Bundle` structure were not allowed.

.. changelog::

:released: March 23, 2024

 .. change::
     :tags: bug, orm
     :tickets: 10611

     Fixed Declarative issue where typing a relationship using
     :class:`_orm.Relationship` rather than :class:`_orm.Mapped` would
     inadvertently pull in the "dynamic" relationship loader strategy for that
     attribute.

 .. change::
     :tags: postgresql, usecase
     :tickets: 10693

     The PostgreSQL dialect now returns :class:`_postgresql.DOMAIN` instances
     when reflecting a column that has a domain as type. Previously, the domain
     data type was returned instead. As part of this change, the domain
     reflection was improved to also return the collation of the text types.
     Pull request courtesy of Thomas Stephenson.

 .. change::
     :tags: bug, typing
     :tickets: 11055

     Fixed typing issue allowing asyncio ``run_sync()`` methods to correctly
     type the parameters according to the callable that was passed, making use
     of :pep:`612` ``ParamSpec`` variables.  Pull request courtesy Francisco R.
     Del Roio.

 .. change::
     :tags: bug, orm
     :tickets: 11091

     Fixed issue in ORM annotated declarative where using
     :func:`_orm.mapped_column()` with an :paramref:`_orm.mapped_column.index`
     or :paramref:`_orm.mapped_column.unique` setting of False would be
     overridden by an incoming ``Annotated`` element that featured that
     parameter set to ``True``, even though the immediate
     :func:`_orm.mapped_column()` element is more specific and should take
     precedence.  The logic to reconcile the booleans has been enhanced to
     accommodate a local value of ``False`` as still taking precedence over an
     incoming ``True`` value from the annotated element.

 .. change::
     :tags: usecase, orm
     :tickets: 11130

     Added support for the :pep:`695` ``TypeAliasType`` construct as well as the
     python 3.12 native ``type`` keyword to work with ORM Annotated Declarative
     form when using these constructs to link to a :pep:`593` ``Annotated``
     container, allowing the resolution of the ``Annotated`` to proceed when
     these constructs are used in a :class:`_orm.Mapped` typing container.

 .. change::
     :tags: bug, engine
     :tickets: 11157

     Fixed issue in :ref:`engine_insertmanyvalues` feature where using a primary
     key column with an "inline execute" default generator such as an explicit
     :class:`.Sequence` with an explcit schema name, while at the same time
     using the
     :paramref:`_engine.Connection.execution_options.schema_translate_map`
     feature would fail to render the sequence or the parameters properly,
     leading to errors.

 .. change::
     :tags: bug, engine
     :tickets: 11160

     Made a change to the adjustment made in version 2.0.10 for :ticket:`9618`,
     which added the behavior of reconciling RETURNING rows from a bulk INSERT
     to the parameters that were passed to it.  This behavior included a
     comparison of already-DB-converted bound parameter values against returned
     row values that was not always "symmetrical" for SQL column types such as
     UUIDs, depending on specifics of how different DBAPIs receive such values
     versus how they return them, necessitating the need for additional
     "sentinel value resolver" methods on these column types.  Unfortunately
     this broke third party column types such as UUID/GUID types in libraries
     like SQLModel which did not implement this special method, raising an error
     "Can't match sentinel values in result set to parameter sets".  Rather than
     attempt to further explain and document this implementation detail of the
     "insertmanyvalues" feature including a public version of the new
     method, the approach is intead revised to no longer need this extra
     conversion step, and the logic that does the comparison now works on the
     pre-converted bound parameter value compared to the post-result-processed
     value, which should always be of a matching datatype.  In the unusual case
     that a custom SQL column type that also happens to be used in a "sentinel"
     column for bulk INSERT is not receiving and returning the same value type,
     the "Can't match" error will be raised, however the mitigation is
     straightforward in that the same Python datatype should be passed as that
     returned.

 .. change::
     :tags: bug, orm, regression
     :tickets: 11173

     Fixed regression from version 2.0.28 caused by the fix for :ticket:`11085`
     where the newer method of adjusting post-cache bound parameter values would
     interefere with the implementation for the :func:`_orm.subqueryload` loader
     option, which has some more legacy patterns in use internally, when
     the additional loader criteria feature were used with this loader option.

 .. change::
     :tags: bug, sql, regression
     :tickets: 11176

     Fixed regression from the 1.4 series where the refactor of the
     :meth:`_types.TypeEngine.with_variant` method introduced at
     :ref:`change_6980` failed to accommodate for the ``.copy()`` method, which
     will lose the variant mappings that are set up. This becomes an issue for
     the very specific case of a "schema" type, which includes types such as
     :class:`.Enum` and :class:`_types.ARRAY`, when they are then used in the context
     of an ORM Declarative mapping with mixins where copying of types comes into
     play.  The variant mapping is now copied as well.

 .. change::
     :tags: bug, tests
     :tickets: 11187

     Backported to SQLAlchemy 2.0 an improvement to the test suite with regards
     to how asyncio related tests are run, now using the newer Python 3.11
     ``asyncio.Runner`` or a backported equivalent, rather than relying on the
     previous implementation based on ``asyncio.get_running_loop()``.  This
     should hopefully prevent issues with large suite runs on CPU loaded
     hardware where the event loop seems to become corrupted, leading to
     cascading failures.


.. changelog::

:released: March 4, 2024

 .. change::
     :tags: engine, usecase
     :tickets: 10974

     Added new core execution option
     :paramref:`_engine.Connection.execution_options.preserve_rowcount`. When
     set, the ``cursor.rowcount`` attribute from the DBAPI cursor will be
     unconditionally memoized at statement execution time, so that whatever
     value the DBAPI offers for any kind of statement will be available using
     the :attr:`_engine.CursorResult.rowcount` attribute from the
     :class:`_engine.CursorResult`.  This allows the rowcount to be accessed for
     statements such as INSERT and SELECT, to the degree supported by the DBAPI
     in use. The :ref:`engine_insertmanyvalues` also supports this option and
     will ensure :attr:`_engine.CursorResult.rowcount` is correctly set for a
     bulk INSERT of rows when set.

 .. change::
     :tags: bug, orm, regression
     :tickets: 11010

     Fixed regression caused by :ticket:`9779` where using the "secondary" table
     in a relationship ``and_()`` expression would fail to be aliased to match
     how the "secondary" table normally renders within a
     :meth:`_sql.Select.join` expression, leading to an invalid query.

 .. change::
     :tags: bug, orm, performance, regression
     :tickets: 11085

     Adjusted the fix made in :ticket:`10570`, released in 2.0.23, where new
     logic was added to reconcile possibly changing bound parameter values
     across cache key generations used within the :func:`_orm.with_expression`
     construct.  The new logic changes the approach by which the new bound
     parameter values are associated with the statement, avoiding the need to
     deep-copy the statement which can result in a significant performance
     penalty for very deep / complex SQL constructs.  The new approach no longer
     requires this deep-copy step.

 .. change::
     :tags: bug, asyncio
     :tickets: 8771

     An error is raised if a :class:`.QueuePool` or other non-asyncio pool class
     is passed to :func:`_asyncio.create_async_engine`.  This engine only
     accepts asyncio-compatible pool classes including
     :class:`.AsyncAdaptedQueuePool`. Other pool classes such as
     :class:`.NullPool` are compatible with both synchronous and asynchronous
     engines as they do not perform any locking.

     .. seealso::

         :ref:`pool_api`


 .. change::
     :tags: change, tests

     pytest support in the tox.ini file has been updated to support pytest 8.1.

.. changelog::

:released: February 13, 2024

 .. change::
     :tags: bug, postgresql, regression
     :tickets: 11005

     Fixed regression caused by just-released fix for :ticket:`10863` where an
     invalid exception class were added to the "except" block, which does not
     get exercised unless such a catch actually happens.   A mock-style test has
     been added to ensure this catch is exercised in unit tests.


.. changelog::

:released: February 11, 2024

 .. change::
     :tags: usecase, postgresql, reflection
     :tickets: 10777

     Added support for reflection of PostgreSQL CHECK constraints marked with
     "NO INHERIT", setting the key ``no_inherit=True`` in the reflected data.
     Pull request courtesy Ellis Valentiner.

 .. change::
     :tags: bug, sql
     :tickets: 10843

     Fixed issues in :func:`_sql.case` where the logic for determining the
     type of the expression could result in :class:`.NullType` if the last
     element in the "whens" had no type, or in other cases where the type
     could resolve to ``None``.  The logic has been updated to scan all
     given expressions so that the first non-null type is used, as well as
     to always ensure a type is present.  Pull request courtesy David Evans.

 .. change::
     :tags: bug, mysql
     :tickets: 10850

     Fixed issue where NULL/NOT NULL would not be properly reflected from a
     MySQL column that also specified the VIRTUAL or STORED directives.  Pull
     request courtesy Georg Wicke-Arndt.

 .. change::
     :tags: bug, regression, postgresql
     :tickets: 10863

     Fixed regression in the asyncpg dialect caused by :ticket:`10717` in
     release 2.0.24 where the change that now attempts to gracefully close the
     asyncpg connection before terminating would not fall back to
     ``terminate()`` for other potential connection-related exceptions other
     than a timeout error, not taking into account cases where the graceful
     ``.close()`` attempt fails for other reasons such as connection errors.


 .. change::
     :tags: oracle, bug, performance
     :tickets: 10877

     Changed the default arraysize of the Oracle dialects so that the value set
     by the driver is used, that is 100 at the time of writing for both
     cx_oracle and oracledb. Previously the value was set to 50 by default. The
     setting of 50 could cause significant performance regressions compared to
     when using cx_oracle/oracledb alone to fetch many hundreds of rows over
     slower networks.

 .. change::
     :tags: bug, mysql
     :tickets: 10893

     Fixed issue in asyncio dialects asyncmy and aiomysql, where their
     ``.close()`` method is apparently not a graceful close.  replace with
     non-standard ``.ensure_closed()`` method that's awaitable and move
     ``.close()`` to the so-called "terminate" case.

 .. change::
     :tags: bug, orm
     :tickets: 10896

     Replaced the "loader depth is excessively deep" warning with a shorter
     message added to the caching badge within SQL logging, for those statements
     where the ORM disabled the cache due to a too-deep chain of loader options.
     The condition which this warning highlights is difficult to resolve and is
     generally just a limitation in the ORM's application of SQL caching. A
     future feature may include the ability to tune the threshold where caching
     is disabled, but for now the warning will no longer be a nuisance.

 .. change::
     :tags: bug, orm
     :tickets: 10899

     Fixed issue where it was not possible to use a type (such as an enum)
     within a :class:`_orm.Mapped` container type if that type were declared
     locally within the class body.  The scope of locals used for the eval now
     includes that of the class body itself.  In addition, the expression within
     :class:`_orm.Mapped` may also refer to the class name itself, if used as a
     string or with future annotations mode.

 .. change::
     :tags: usecase, postgresql
     :tickets: 10904

     Support the ``USING <method>`` option for PostgreSQL ``CREATE TABLE`` to
     specify the access method to use to store the contents for the new table.
     Pull request courtesy Edgar Ramírez-Mondragón.

     .. seealso::

         :ref:`postgresql_table_options`

 .. change::
     :tags: bug, examples
     :tickets: 10920

     Fixed regression in history_meta example where the use of
     :meth:`_schema.MetaData.to_metadata` to make a copy of the history table
     would also copy indexes (which is a good thing), but causing naming
     conflicts indexes regardless of naming scheme used for those indexes. A
     "_history" suffix is now added to these indexes in the same way as is
     achieved for the table name.


 .. change::
     :tags: bug, orm
     :tickets: 10967

     Fixed issue where using :meth:`_orm.Session.delete` along with the
     :paramref:`_orm.Mapper.version_id_col` feature would fail to use the
     correct version identifier in the case that an additional UPDATE were
     emitted against the target object as a result of the use of
     :paramref:`_orm.relationship.post_update` on the object.  The issue is
     similar to :ticket:`10800` just fixed in version 2.0.25 for the case of
     updates alone.

 .. change::
     :tags: bug, orm
     :tickets: 10990

     Fixed issue where an assertion within the implementation for
     :func:`_orm.with_expression` would raise if a SQL expression that was not
     cacheable were used; this was a 2.0 regression since 1.4.

 .. change::
     :tags: postgresql, usecase
     :tickets: 9736

     Correctly type PostgreSQL RANGE and MULTIRANGE types as ``Range[T]``
     and ``Sequence[Range[T]]``.
     Introduced utility sequence :class:`_postgresql.MultiRange` to allow better
     interoperability of MULTIRANGE types.

 .. change::
     :tags: postgresql, usecase

     Differentiate between INT4 and INT8 ranges and multi-ranges types when
     inferring the database type from a :class:`_postgresql.Range` or
     :class:`_postgresql.MultiRange` instance, preferring INT4 if the values
     fit into it.

 .. change::
     :tags: bug, typing

     Fixed the type signature for the :meth:`.PoolEvents.checkin` event to
     indicate that the given :class:`.DBAPIConnection` argument may be ``None``
     in the case where the connection has been invalidated.

 .. change::
     :tags: bug, examples

     Fixed the performance example scripts in examples/performance to mostly
     work with the Oracle database, by adding the :class:`.Identity` construct
     to all the tables and allowing primary generation to occur on this backend.
     A few of the "raw DBAPI" cases still are not compatible with Oracle.


 .. change::
     :tags: bug, mssql

     Fixed an issue regarding the use of the :class:`.Uuid` datatype with the
     :paramref:`.Uuid.as_uuid` parameter set to False, when using the pymssql
     dialect. ORM-optimized INSERT statements (e.g. the "insertmanyvalues"
     feature) would not correctly align primary key UUID values for bulk INSERT
     statements, resulting in errors.  Similar issues were fixed for the
     PostgreSQL drivers as well.


 .. change::
     :tags: bug, postgresql

     Fixed an issue regarding the use of the :class:`.Uuid` datatype with the
     :paramref:`.Uuid.as_uuid` parameter set to False, when using PostgreSQL
     dialects. ORM-optimized INSERT statements (e.g. the "insertmanyvalues"
     feature) would not correctly align primary key UUID values for bulk INSERT
     statements, resulting in errors.  Similar issues were fixed for the
     pymssql driver as well.

.. changelog::

:released: January 2, 2024

 .. change::
     :tags: oracle, asyncio
     :tickets: 10679

     Added support for :ref:`oracledb` in asyncio mode, using the newly released
     version of the ``oracledb`` DBAPI that includes asyncio support. For the
     2.0 series, this is a preview release, where the current implementation
     does not yet have include support for
     :meth:`_asyncio.AsyncConnection.stream`. Improved support is planned for
     the 2.1 release of SQLAlchemy.

 .. change::
     :tags: bug, orm
     :tickets: 10800

     Fixed issue where when making use of the
     :paramref:`_orm.relationship.post_update` feature at the same time as using
     a mapper version_id_col could lead to a situation where the second UPDATE
     statement emitted by the post-update feature would fail to make use of the
     correct version identifier, assuming an UPDATE was already emitted in that
     flush which had already bumped the version counter.

 .. change::
     :tags: bug, typing
     :tickets: 10801, 10818

     Fixed regressions caused by typing added to the ``sqlalchemy.sql.functions``
     module in version 2.0.24, as part of :ticket:`6810`:

     * Further enhancements to pep-484 typing to allow SQL functions from
       :attr:`_sql.func` derived elements to work more effectively with ORM-mapped
       attributes (:ticket:`10801`)

     * Fixed the argument types passed to functions so that literal expressions
       like strings and ints are again interpreted correctly (:ticket:`10818`)


 .. change::
     :tags: usecase, orm
     :tickets: 10807

     Added preliminary support for Python 3.12 pep-695 type alias structures,
     when resolving custom type maps for ORM Annotated Declarative mappings.


 .. change::
     :tags: bug, orm
     :tickets: 10815

     Fixed issue where ORM Annotated Declarative would mis-interpret the left
     hand side of a relationship without any collection specified as
     uselist=True if the left type were given as a class and not a string,
     without using future-style annotations.

 .. change::
     :tags: bug, sql
     :tickets: 10817

     Improved compilation of :func:`_sql.any_` / :func:`_sql.all_` in the
     context of a negation of boolean comparison, will now render ``NOT (expr)``
     rather than reversing the equality operator to not equals, allowing
     finer-grained control of negations for these non-typical operators.

.. changelog::

:released: December 28, 2023

 .. change::
     :tags: bug, orm
     :tickets: 10597

     Fixed issue where use of :func:`_orm.foreign` annotation on a
     non-initialized :func:`_orm.mapped_column` construct would produce an
     expression without a type, which was then not updated at initialization
     time of the actual column, leading to issues such as relationships not
     determining ``use_get`` appropriately.


 .. change::
     :tags: bug, schema
     :tickets: 10654

     Fixed issue where error reporting for unexpected schema item when creating
     objects like :class:`_schema.Table` would incorrectly handle an argument
     that was itself passed as a tuple, leading to a formatting error.  The
     error message has been modernized to use f-strings.

 .. change::
     :tags: bug, engine
     :tickets: 10662

     Fixed URL-encoding of the username and password components of
     :class:`.engine.URL` objects when converting them to string using the
     :meth:`_engine.URL.render_as_string` method, by using Python standard
     library ``urllib.parse.quote`` while allowing for plus signs and spaces to
     remain unchanged as supported by SQLAlchemy's non-standard URL parsing,
     rather than the legacy home-grown routine from many years ago. Pull request
     courtesy of Xavier NUNN.

 .. change::
     :tags: bug, orm
     :tickets: 10668

     Improved the error message produced when the unit of work process sets the
     value of a primary key column to NULL due to a related object with a
     dependency rule on that column being deleted, to include not just the
     destination object and column name but also the source column from which
     the NULL value is originating.  Pull request courtesy Jan Vollmer.

 .. change::
     :tags: bug, postgresql
     :tickets: 10717

     Adjusted the asyncpg dialect such that when the ``terminate()`` method is
     used to discard an invalidated connection, the dialect will first attempt
     to gracefully close the connection using ``.close()`` with a timeout, if
     the operation is proceeding within an async event loop context only. This
     allows the asyncpg driver to attend to finalizing a ``TimeoutError``
     including being able to close a long-running query server side, which
     otherwise can keep running after the program has exited.

 .. change::
     :tags: bug, orm
     :tickets: 10732

     Modified the ``__init_subclass__()`` method used by
     :class:`_orm.MappedAsDataclass`, :class:`_orm.DeclarativeBase` and
     :class:`_orm.DeclarativeBaseNoMeta` to accept arbitrary ``**kw`` and to
     propagate them to the ``super()`` call, allowing greater flexibility in
     arranging custom superclasses and mixins which make use of
     ``__init_subclass__()`` keyword arguments.  Pull request courtesy Michael
     Oliver.


 .. change::
     :tags: bug, tests
     :tickets: 10747

     Improvements to the test suite to further harden its ability to run
     when Python ``greenlet`` is not installed.   There is now a tox
     target that includes the token "nogreenlet" that will run the suite
     with greenlet not installed (note that it still temporarily installs
     greenlet as part of the tox config, however).

 .. change::
     :tags: bug, sql
     :tickets: 10753

     Fixed issue in stringify for SQL elements, where a specific dialect is not
     passed,  where a dialect-specific element such as the PostgreSQL "on
     conflict do update" construct is encountered and then fails to provide for
     a stringify dialect with the appropriate state to render the construct,
     leading to internal errors.

 .. change::
     :tags: bug, sql

     Fixed issue where stringifying or compiling a :class:`.CTE` that was
     against a DML construct such as an :func:`_sql.insert` construct would fail
     to stringify, due to a mis-detection that the statement overall is an
     INSERT, leading to internal errors.

 .. change::
     :tags: bug, orm
     :tickets: 10776

     Ensured the use case of :class:`.Bundle` objects used in the
     ``returning()`` portion of ORM-enabled INSERT, UPDATE and DELETE statements
     is tested and works fully.   This was never explicitly implemented or
     tested previously and did not work correctly in the 1.4 series; in the 2.0
     series, ORM UPDATE/DELETE with WHERE criteria was missing an implementation
     method preventing :class:`.Bundle` objects from working.

 .. change::
     :tags: bug, orm
     :tickets: 10784

     Fixed 2.0 regression in :class:`.MutableList` where a routine that detects
     sequences would not correctly filter out string or bytes instances, making
     it impossible to assign a string value to a specific index (while
     non-sequence values would work fine).

 .. change::
     :tags: change, asyncio

     The ``async_fallback`` dialect argument is now deprecated, and will be
     removed in SQLAlchemy 2.1.   This flag has not been used for SQLAlchemy's
     test suite for some time.   asyncio dialects can still run in a synchronous
     style by running code within a greenlet using :func:`_util.greenlet_spawn`.

 .. change::
    :tags: bug, typing
    :tickets: 6810

    Completed pep-484 typing for the ``sqlalchemy.sql.functions`` module.
    :func:`_sql.select` constructs made against ``func`` elements should now
    have filled-in return types.

.. changelog::

:released: November 2, 2023

 .. change::
     :tags: bug, oracle
     :tickets: 10509

     Fixed issue in :class:`.Interval` datatype where the Oracle implementation
     was not being used for DDL generation, leading to the ``day_precision`` and
     ``second_precision`` parameters to be ignored, despite being supported by
     this dialect.  Pull request courtesy Indivar.

 .. change::
     :tags: bug, orm
     :tickets: 10516

     Fixed issue where the ``__allow_unmapped__`` directive failed to allow for
     legacy :class:`.Column` / :func:`.deferred` mappings that nonetheless had
     annotations such as ``Any`` or a specific type without ``Mapped[]`` as
     their type, without errors related to locating the attribute name.

 .. change::
     :tags: bug, mariadb
     :tickets: 10056

     Adjusted the MySQL / MariaDB dialects to default a generated column to NULL
     when using MariaDB, if :paramref:`_schema.Column.nullable` was not
     specified with an explicit ``True`` or ``False`` value, as MariaDB does not
     support the "NOT NULL" phrase with a generated column.  Pull request
     courtesy Indivar.


 .. change::
     :tags: bug, mariadb, regression
     :tickets: 10505

     Established a workaround for what seems to be an intrinsic issue across
     MySQL/MariaDB drivers where a RETURNING result for DELETE DML which returns
     no rows using SQLAlchemy's "empty IN" criteria fails to provide a
     cursor.description, which then yields result that returns no rows,
     leading to regressions for the ORM that in the 2.0 series uses RETURNING
     for bulk DELETE statements for the "synchronize session" feature. To
     resolve, when the specific case of "no description when RETURNING was
     given" is detected, an "empty result" with a correct cursor description is
     generated and used in place of the non-working cursor.

 .. change::
     :tags: bug, orm
     :tickets: 10570

     Fixed caching bug where using the :func:`_orm.with_expression` construct in
     conjunction with loader options :func:`_orm.selectinload`,
     :func:`_orm.lazyload` would fail to substitute bound parameter values
     correctly on subsequent caching runs.

 .. change::
     :tags: usecase, mssql
     :tickets: 6521

     Added support for the ``aioodbc`` driver implemented for SQL Server,
     which builds on top of the pyodbc and general aio* dialect architecture.

     .. seealso::

         :ref:`mssql_aioodbc` - in the SQL Server dialect documentation.



 .. change::
     :tags: bug, sql
     :tickets: 10535

     Added compiler-level None/NULL handling for the "literal processors" of all
     datatypes that include literal processing, that is, where a value is
     rendered inline within a SQL statement rather than as a bound parameter,
     for all those types that do not feature explicit "null value" handling.
     Previously this behavior was undefined and inconsistent.

 .. change::
     :tags: usecase, orm
     :tickets: 10575

     Implemented the :paramref:`_orm.Session.bulk_insert_mappings.render_nulls`
     parameter for new style bulk ORM inserts, allowing ``render_nulls=True`` as
     an execution option.   This allows for bulk ORM inserts with a mixture of
     ``None`` values in the parameter dictionaries to use a single batch of rows
     for a given set of dicationary keys, rather than breaking up into batches
     that omit the NULL columns from each INSERT.

     .. seealso::

         :ref:`orm_queryguide_insert_null_params`

 .. change::
     :tags: bug, postgresql
     :tickets: 10479

     Fixed 2.0 regression caused by :ticket:`7744` where chains of expressions
     involving PostgreSQL JSON operators combined with other operators such as
     string concatenation would lose correct parenthesization, due to an
     implementation detail specific to the PostgreSQL dialect.

 .. change::
     :tags: bug, postgresql
     :tickets: 10532

     Fixed SQL handling for "insertmanyvalues" when using the
     :class:`.postgresql.BIT` datatype with the asyncpg backend.  The
     :class:`.postgresql.BIT` on asyncpg apparently requires the use of an
     asyncpg-specific ``BitString`` type which is currently exposed when using
     this DBAPI, making it incompatible with other PostgreSQL DBAPIs that all
     work with plain bitstrings here.  A future fix in version 2.1 will
     normalize this datatype across all PG backends.   Pull request courtesy
     Sören Oldag.


 .. change::
     :tags: usecase, sql
     :tickets: 9737

     Implemented "literal value processing" for the :class:`.Interval` datatype
     for both the PostgreSQL and Oracle dialects, allowing literal rendering of
     interval values.  Pull request courtesy Indivar Mishra.

 .. change::
     :tags: bug, oracle
     :tickets: 10470

     Fixed issue where the cx_Oracle dialect claimed to support a lower
     cx_Oracle version (7.x) than was actually supported in practice within the
     2.0 series of SQLAlchemy. The dialect imports symbols that are only in
     cx_Oracle 8 or higher, so runtime dialect checks as well as setup.cfg
     requirements have been updated to reflect this compatibility.

 .. change::
     :tags: sql

     Removed unused placeholder method :meth:`.TypeEngine.compare_against_backend`
     This method was used by very old versions of Alembic.
     See https://github.com/sqlalchemy/alembic/issues/1293 for details.

 .. change::
     :tags: bug, orm
     :tickets: 10472

     Fixed bug in ORM annotated declarative where using a ``ClassVar`` that
     nonetheless referred in some way to an ORM mapped class name would fail to
     be interpreted as a ``ClassVar`` that's not mapped.

 .. change::
     :tags: bug, asyncio
     :tickets: 10421

     Fixed bug with method :meth:`_asyncio.AsyncSession.close_all`
     that was not working correctly.
     Also added function :func:`_asyncio.close_all_sessions` that's
     the equivalent of :func:`_orm.close_all_sessions`.
     Pull request courtesy of Bryan不可思议.

.. changelog::

:released: October 12, 2023

 .. change::
     :tags: bug, orm
     :tickets: 10369, 10046

     Fixed a wide range of :func:`_orm.mapped_column` parameters that were not
     being transferred when using the :func:`_orm.mapped_column` object inside
     of a pep-593 ``Annotated`` object, including
     :paramref:`_orm.mapped_column.sort_order`,
     :paramref:`_orm.mapped_column.deferred`,
     :paramref:`_orm.mapped_column.autoincrement`,
     :paramref:`_orm.mapped_column.system`, :paramref:`_orm.mapped_column.info`
     etc.

     Additionally, it remains not supported to have dataclass arguments, such as
     :paramref:`_orm.mapped_column.kw_only`,
     :paramref:`_orm.mapped_column.default_factory` etc. indicated within the
     :func:`_orm.mapped_column` received by ``Annotated``, as this is not
     supported with pep-681 Dataclass Transforms.  A warning is now emitted when
     these parameters are used within ``Annotated`` in this way (and they
     continue to be ignored).

 .. change::
     :tags: bug, orm
     :tickets: 10459

     Fixed issue where calling :meth:`_engine.Result.unique` with a new-style
     :func:`.select` query in the ORM, where one or more columns yields values
     that are of "unknown hashability", typically when using JSON functions like
     ``func.json_build_object()`` without providing a type, would fail
     internally when the returned values were not actually hashable. The
     behavior is repaired to test the objects as they are received for
     hashability in this case, raising an informative error message if not. Note
     that for values of "known unhashability", such as when the
     :class:`_types.JSON` or :class:`_types.ARRAY` types are used directly, an
     informative error message was already raised.

     The "hashabiltiy testing" fix here is applied to legacy :class:`.Query` as
     well, however in the legacy case, :meth:`_engine.Result.unique` is used for
     nearly all queries, so no new warning is emitted here; the legacy behavior
     of falling back to using ``id()`` in this case is maintained, with the
     improvement that an unknown type that turns out to be hashable will now be
     uniqufied, whereas previously it would not.

 .. change::
     :tags: bug, orm
     :tickets: 10453

     Fixed regression in recently revised "insertmanyvalues" feature (likely
     issue :ticket:`9618`) where the ORM would inadvertently attempt to
     interpret a non-RETURNING result as one with RETURNING, in the case where
     the ``implicit_returning=False`` parameter were applied to the mapped
     :class:`.Table`, indicating that "insertmanyvalues" cannot be used if the
     primary key values are not provided.

 .. change::
     :tags: bug, engine

     Fixed issue within some dialects where the dialect could incorrectly return
     an empty result set for an INSERT statement that does not actually return
     rows at all, due to artfacts from pre- or post-fetching the primary key of
     the row or rows still being present.  Affected dialects included asyncpg,
     all mssql dialects.

 .. change::
     :tags: bug, typing
     :tickets: 10451

     Fixed typing issue where the argument list passed to :class:`.Values` was
     too-restrictively tied to ``List`` rather than ``Sequence``.  Pull request
     courtesy Iuri de Silvio.

 .. change::
     :tags: bug, orm
     :tickets: 10365, 11412

     Fixed bug where ORM :func:`_orm.with_loader_criteria` would not apply
     itself to a :meth:`_sql.Select.join` where the ON clause were given as a
     plain SQL comparison, rather than as a relationship target or similar.

     **update** - this was found to also fix an issue where
     single-inheritance criteria would not be correctly applied to a
     subclass entity that only appeared in the ``select_from()`` list,
     see :ticket:`11412`

 .. change::
     :tags: bug, sql
     :tickets: 10408

     Fixed issue where referring to a FROM entry in the SET clause of an UPDATE
     statement would not include it in the FROM clause of the UPDATE statement,
     if that entry were nowhere else in the statement; this occurs currently for
     CTEs that were added using :meth:`.Update.add_cte` to provide the desired
     CTE at the top of the statement.

 .. change::
     :tags: bug, mariadb
     :tickets: 10396

     Modified the mariadb-connector driver to pre-load the ``cursor.rowcount``
     value for all queries, to suit tools such as Pandas that hardcode to
     calling :attr:`.Result.rowcount` in this way. SQLAlchemy normally pre-loads
     ``cursor.rowcount`` only for UPDATE/DELETE statements and otherwise passes
     through to the DBAPI where it can return -1 if no value is available.
     However, mariadb-connector does not support invoking ``cursor.rowcount``
     after the cursor itself is closed, raising an error instead.  Generic test
     support has been added to ensure all backends support the allowing
     :attr:`.Result.rowcount` to succceed (that is, returning an integer
     value with -1 for "not available") after the result is closed.



 .. change::
     :tags: bug, mariadb

     Additional fixes for the mariadb-connector dialect to support UUID data
     values in the result in INSERT..RETURNING statements.

 .. change::
     :tags: bug, mssql
     :tickets: 10458

     Fixed bug where the rule that prevents ORDER BY from emitting within
     subqueries on SQL Server was not being disabled in the case where the
     :meth:`.select.fetch` method were used to limit rows in conjunction with
     WITH TIES or PERCENT, preventing valid subqueries with TOP / ORDER BY from
     being used.



 .. change::
     :tags: bug, sql
     :tickets: 10443

     Fixed 2.0 regression where the :class:`.DDL` construct would no longer
     ``__repr__()`` due to the removed ``on`` attribute not being accommodated.
     Pull request courtesy Iuri de Silvio.

 .. change::
     :tags: orm, usecase
     :tickets: 10202

     Added method :meth:`_orm.Session.get_one` that behaves like
     :meth:`_orm.Session.get` but raises an exception instead of returning
     ``None`` if no instance was found with the provided primary key.
     Pull request courtesy of Carlos Sousa.


 .. change::
     :tags: asyncio, bug

     Fixed the :paramref:`_asyncio.AsyncSession.get.execution_options` parameter
     which was not being propagated to the underlying :class:`_orm.Session` and
     was instead being ignored.

 .. change::
     :tags: bug, orm
     :tic