2.0.4

Released: February 17, 2023

orm

• [orm] [usecase] The _orm.Session.refresh() method will now immediately load a relationship-bound attribute that is explicitly named within the _orm.Session.refresh.attribute_names collection even if it is currently linked to the "select" loader, which normally is a "lazy" loader that does not fire off during a refresh. The "lazy loader" strategy will now detect that the operation is specifically a user-initiated _orm.Session.refresh() operation which named this attribute explicitly, and will then call upon the "immediateload" strategy to actually emit SQL to load the attribute. This should be helpful in particular for some asyncio situations where the loading of an unloaded lazy-loaded attribute must be forced, without using the actual lazy-loading attribute pattern not supported in asyncio.

  References: #9298

• [orm] [bug] [regression] Fixed regression introduced in version 2.0.2 due to #9217 where using DML RETURNING statements, as well as _sql.Select.from_statement() constructs as was "fixed" in #9217, in conjunction with ORM mapped classes that used expressions such as with _orm.column_property(), would lead to an internal error within Core where it would attempt to match the expression by name. The fix repairs the Core issue, and also adjusts the fix in #9217 to not take effect for the DML RETURNING use case, where it adds unnecessary overhead.

  References: #9273

• [orm] [bug] Marked the internal EvaluatorCompiler module as private to the ORM, and renamed it to _EvaluatorCompiler. For users that may have been relying upon this, the name EvaluatorCompiler is still present, however this use is not supported and will be removed in a future release.

• [orm] [use_case] To accommodate a change in column ordering used by ORM Declarative in SQLAlchemy 2.0, a new parameter _orm.mapped_column.sort_order has been added that can be used to control the order of the columns defined in the table by the ORM, for common use cases such as mixins with primary key columns that should appear first in tables. The change notes at change_9297 illustrate the default change in ordering behavior (which is part of all SQLAlchemy 2.0 releases) as well as use of the _orm.mapped_column.sort_order to control column ordering when using mixins and multiple classes (new in 2.0.4).

  References: #9297

orm declarative

• [usecase] [orm declarative] Added new parameter dataclasses_callable to both the _orm.MappedAsDataclass class as well as the _orm.registry.mapped_as_dataclass() method which allows an alternative callable to Python dataclasses.dataclass to be used in order to produce dataclasses. The use case here is to drop in Pydantic's dataclass function instead. Adjustments have been made to the mixin support added for #9179 in version 2.0.1 so that the __annotations__ collection of the mixin is rewritten to not include the _orm.Mapped container, in the same way as occurs with mapped classes, so that the Pydantic dataclasses constructor is not exposed to unknown types.

  References: #9266

sql

• [sql] [bug] Fixed issue where element types of a tuple value would be hardcoded to take on the types from a compared-to tuple, when the comparison were using the ColumnOperators.in_() operator. This was inconsistent with the usual way that types are determined for a binary expression, which is that the actual element type on the right side is considered first before applying the left-hand-side type.

  References: #9313

• [sql] Added public property _schema.Table.autoincrement_column that returns the column identified as autoincrementing in the column.

  References: #9277

typing

• [typing] [usecase] Improved the typing support for the hybrids_toplevel extension, updated all documentation to use ORM Annotated Declarative mappings, and added a new modifier called hybrid_property.inplace. This modifier provides a way to alter the state of a hybrid_property in place, which is essentially what very early versions of hybrids did, before SQLAlchemy version 1.2.0 #3912 changed this to remove in-place mutation. This in-place mutation is now restored on an opt-in basis to allow a single hybrid to have multiple methods set up, without the need to name all the methods the same and without the need to carefully "chain" differently-named methods in order to maintain the composition. Typing tools such as Mypy and Pyright do not allow same-named methods on a class, so with this change a succinct method of setting up hybrids with typing support is restored.

  References: #9321

oracle

• [oracle] [bug] Adjusted the behavior of the thick_mode parameter for the oracledb dialect to correctly accept False as a value. Previously, only None would indicate that thick mode should be disabled.

  References: #9295