2.0.46

Released: January 21, 2026

typing

[typing] [bug] Fixed typing issues where ORM mapped classes and aliased entities could not
be used as keys in result row mappings or as join targets in select
statements. Patterns such as row._mapping[User],
row._mapping[aliased(User)], row._mapping[with_polymorphic(...)]
(rejected by both mypy and Pylance), and .join(aliased(User))
(rejected by Pylance) are documented and fully supported at runtime but
were previously rejected by type checkers. The type definitions for
_KeyType and _FromClauseArgument have been updated to
accept these ORM entity types.

References: #13075

[postgresql] [bug] Fixed issue where PostgreSQL JSONB operators
_postgresql.JSONB.Comparator.path_match() and
_postgresql.JSONB.Comparator.path_exists() were applying incorrect
VARCHAR casts to the right-hand side operand when used with newer
PostgreSQL drivers such as psycopg. The operators now indicate the
right-hand type as JSONPATH, which currently results in no casting
taking place, but is also compatible with explicit casts if the
implementation were require it at a later point.

References: #13059
[postgresql] [bug] Fixed regression in PostgreSQL dialect where JSONB subscription syntax
would generate incorrect SQL for cast() expressions returning JSONB,
causing syntax errors. The dialect now properly wraps cast expressions in
parentheses when using the [] subscription syntax, generating
(CAST(...))[index] instead of CAST(...)[index] to comply with
PostgreSQL syntax requirements. This extends the fix from #12778
which addressed the same issue for function calls.

References: #13067
[postgresql] [bug] Improved the foreign key reflection regular expression pattern used by the
PostgreSQL dialect to be more permissive in matching identifier characters,
allowing it to correctly handle unicode characters in table and column
names. This change improves compatibility with PostgreSQL variants such as
CockroachDB that may use different quoting patterns in combination with
unicode characters in their identifiers. Pull request courtesy Gord
Thompson.

[mariadb] [bug] Fixed the SQL compilation for the mariadb sequence "NOCYCLE" keyword that
is to be emitted when the Sequence.cycle parameter is set to
False on a Sequence. Pull request courtesy Diego Dupin.

References: #13070

[sqlite] [bug] Fixed issue in the aiosqlite driver where SQLAlchemy's setting of
aiosqlite's worker thread to "daemon" stopped working because the aiosqlite
architecture moved the location of the worker thread in version 0.22.0.
This "daemon" flag is necessary so that a program is able to exit if the
SQLite connection itself was not explicitly closed, which is particularly
likely with SQLAlchemy as it maintains SQLite connections in a connection
pool. While it's perfectly fine to call AsyncEngine.dispose()
before program exit, this is not historically or technically necessary for
any driver of any known backend, since a primary feature of relational
databases is durability. The change also implements support for
"terminate" with aiosqlite when using version version 0.22.1 or greater,
which implements a sync .stop() method.

References: #13039

[mssql] [usecase] Added support for the IF EXISTS clause when dropping indexes on SQL
Server 2016 (13.x) and later versions. The DropIndex.if_exists
parameter is now honored by the SQL Server dialect, allowing conditional
index drops that will not raise an error if the index does not exist.
Pull request courtesy Edgar Ramírez Mondragón.

References: #13045