sqlalchemy.orm.util._TraceAdaptRole

Enumeration of all the use cases for ORMAdapter. ORMAdapter remains one of the most complicated aspects of the ORM, as it is used for in-place adaption of column expressions to be applied to a SELECT, replacing :class:`.Table` and other objects that are mapped to classes with aliases of those tables in the case of joined eager loading, or in the case of polymorphic loading as used with concrete mappings or other custom "with polymorphic" parameters, with whole user-defined subqueries. The enumerations provide an overview of all the use cases used by ORMAdapter, a layer of formality as to the introduction of new ORMAdapter use cases (of which none are anticipated), as well as a means to trace the origins of a particular ORMAdapter within runtime debugging. SQLAlchemy 2.0 has greatly scaled back ORM features which relied heavily on open-ended statement adaption, including the ``Query.with_polymorphic()`` method and the ``Query.select_from_entity()`` methods, favoring user-explicit aliasing schemes using the ``aliased()`` and ``with_polymorphic()`` standalone constructs; these still use adaption, however the adaption is applied in a narrower scope.