Runtime Inspection API

The inspection module provides the inspect() function, which delivers runtime information about a wide variety of SQLAlchemy objects, both within the Core as well as the ORM.

The inspect() function is the entry point to SQLAlchemy’s public API for viewing the configuration and construction of in-memory objects. Depending on the type of object passed to inspect(), the return value will either be a related object which provides a known interface, or in many cases it will return the object itself.

The rationale for inspect() is twofold. One is that it replaces the need to be aware of a large variety of “information getting” functions in SQLAlchemy, such as Inspector.from_engine() (deprecated in 1.4), instance_state(), class_mapper(), and others. The other is that the return value of inspect() is guaranteed to obey a documented API, thus allowing third party tools which build on top of SQLAlchemy configurations to be constructed in a forwards-compatible way.

Object Name Description

inspect(subject[, raiseerr])

Produce an inspection object for the given target.

function sqlalchemy.inspect(subject, raiseerr=True)

Produce an inspection object for the given target.

The returned value in some cases may be the same object as the one given, such as if a Mapper object is passed. In other cases, it will be an instance of the registered inspection type for the given object, such as if an Engine is passed, an Inspector object is returned.

  • subject – the subject to be inspected.

  • raiseerr – When True, if the given subject does not correspond to a known SQLAlchemy inspected type, sqlalchemy.exc.NoInspectionAvailable is raised. If False, None is returned.

Available Inspection Targets

Below is a listing of many of the most common inspection targets.