sqlalchemy.orm.attributes.Mapped

class documentation

class Mapped(QueryableAttribute, _Generic_T):

Known subclasses: sqlalchemy.orm.attributes.InstrumentedAttribute

Represent an ORM mapped :term:`descriptor` attribute for typing purposes.

This class represents the complete descriptor interface for any class attribute that will have been :term:`instrumented` by the ORM _orm.Mapper class. When used with typing stubs, it is the final type that would be used by a type checker such as mypy to provide the full behavioral contract for the attribute.

Tip

The _orm.Mapped class represents attributes that are handled directly by the _orm.Mapper class. It does not include other Python descriptor classes that are provided as extensions, including :ref:`hybrids_toplevel` and the :ref:`associationproxy_toplevel`. While these systems still make use of ORM-specific superclasses and structures, they are not :term:`instrumented` by the _orm.Mapper and instead provide their own functionality when they are accessed on a class.

When using the :ref:`SQLAlchemy Mypy plugin <mypy_toplevel>`, the _orm.Mapped construct is used in typing annotations to indicate to the plugin those attributes that are expected to be mapped; the plugin also applies _orm.Mapped as an annotation automatically when it scans through declarative mappings in :ref:`orm_declarative_table` style. For more indirect mapping styles such as :ref:`imperative table <orm_imperative_table_configuration>` it is typically applied explicitly to class level attributes that expect to be mapped based on a given _schema.Table configuration.

_orm.Mapped is defined in the sqlalchemy2-stubs project as a PEP 484 generic class which may subscribe to any arbitrary Python type, which represents the Python type handled by the attribute:

class MyMappedClass(Base):
    __table_ = Table(
        "some_table", Base.metadata,
        Column("id", Integer, primary_key=True),
        Column("data", String(50)),
        Column("created_at", DateTime)
    )

    id : Mapped[int]
    data: Mapped[str]
    created_at: Mapped[datetime]

For complete background on how to use _orm.Mapped with pep-484 tools like Mypy, see the link below for background on SQLAlchemy's Mypy plugin.

New in version 1.4.

See Also

:ref:`mypy_toplevel` - complete background on Mypy integration

Method	`__delete__`	Undocumented
Method	`__get__`	Undocumented
Method	`__set__`	Undocumented

Inherited from QueryableAttribute:

Method	`__clause_element__`	Undocumented
Method	`__getattr__`	Undocumented
Method	`__init__`	Undocumented
Method	`__reduce__`	Undocumented
Method	`__str__`	Undocumented
Method	`_bulk_update_tuples`	Return setter tuples for a bulk UPDATE.
Method	`_clone`	Undocumented
Method	`adapt_to_entity`	Return a copy of this PropComparator which will use the given `.AliasedInsp` to produce corresponding expressions.
Method	`and_`	Add additional criteria to the ON clause that's represented by this relationship attribute.
Method	`get_history`	Undocumented
Method	`hasparent`	Undocumented
Method	`label`	Undocumented
Method	`of_type`	Redefine this object in terms of a polymorphic subclass, `_orm.with_polymorphic` construct, or `_orm.aliased` construct.
Method	`operate`	Operate on an argument.
Method	`reverse_operate`	Reverse operate on an argument.
Class Variable	`__visit_name__`	Undocumented
Class Variable	`_cache_key_traversal`	Undocumented
Class Variable	`is_attribute`	True if this object is a Python :term:`descriptor`.
Instance Variable	`_extra_criteria`	Undocumented
Instance Variable	`_of_type`	Undocumented
Instance Variable	`_parententity`	Undocumented
Instance Variable	`class_`	Undocumented
Instance Variable	`comparator`	Undocumented
Instance Variable	`impl`	Undocumented
Instance Variable	`key`	Undocumented
Property	`_annotations`	Undocumented
Property	`_entity_namespace`	Undocumented
Property	`_from_objects`	Undocumented
Property	`_impl_uses_objects`	Undocumented
Property	`_supports_population`	Undocumented
Property	`expression`	The SQL expression object represented by this `.QueryableAttribute`.
Property	`info`	Return the 'info' dictionary for the underlying SQL element.
Property	`parent`	Return an inspection instance representing the parent.
Property	`property`	Return the `.MapperProperty` associated with this `.QueryableAttribute`.

Inherited from _MappedAttribute (via QueryableAttribute):

Class Variable __slots__ Undocumented

Inherited from InspectionAttr (via QueryableAttribute):

Class Variable	`__slots__`	Undocumented
Class Variable	`_is_internal_proxy`	True if this object is an internal proxy object.
Class Variable	`is_aliased_class`	True if this object is an instance of `.AliasedClass`.
Class Variable	`is_bundle`	True if this object is an instance of `.Bundle`.
Class Variable	`is_clause_element`	True if this object is an instance of `_expression.ClauseElement`.
Class Variable	`is_instance`	True if this object is an instance of `.InstanceState`.
Class Variable	`is_mapper`	True if this object is an instance of `_orm.Mapper`.
Class Variable	`is_property`	True if this object is an instance of `.MapperProperty`.
Class Variable	`is_selectable`	Return True if this object is an instance of `_expression.Selectable`.

Inherited from PropComparator (via QueryableAttribute):

Static Method	`any_op`	Undocumented
Static Method	`has_op`	Undocumented
Static Method	`of_type_op`	Undocumented
Method	`any`	Return true if this collection contains any member that meets the given criterion.
Method	`has`	Return true if this element references a member which meets the given criterion.
Class Variable	`__slots__`	Undocumented
Instance Variable	`_adapt_to_entity`	Undocumented
Instance Variable	`prop`	Undocumented
Property	`_parentmapper`	legacy; this is renamed to _parententity to be compatible with QueryableAttribute.
Property	`_propagate_attrs`	Undocumented
Property	`adapter`	Produce a callable that adapts column expressions to suit an aliased version of this comparator.

Inherited from ColumnOperators (via QueryableAttribute, PropComparator):

Method	`__add__`	Implement the `+` operator.
Method	`__contains__`	Undocumented
Method	`__div__`	Implement the `/` operator.
Method	`__eq__`	Implement the `==` operator.
Method	`__ge__`	Implement the `>=` operator.
Method	`__getitem__`	Implement the [] operator.
Method	`__gt__`	Implement the `>` operator.
Method	`__le__`	Implement the `<=` operator.
Method	`__lshift__`	implement the << operator.
Method	`__lt__`	Implement the `<` operator.
Method	`__mod__`	Implement the `%` operator.
Method	`__mul__`	Implement the `*` operator.
Method	`__ne__`	Implement the `!=` operator.
Method	`__neg__`	Implement the `-` operator.
Method	`__radd__`	Implement the `+` operator in reverse.
Method	`__rdiv__`	Implement the `/` operator in reverse.
Method	`__rmod__`	Implement the `%` operator in reverse.
Method	`__rmul__`	Implement the `*` operator in reverse.
Method	`__rshift__`	implement the >> operator.
Method	`__rsub__`	Implement the `-` operator in reverse.
Method	`__rtruediv__`	Implement the `//` operator in reverse.
Method	`__sub__`	Implement the `-` operator.
Method	`__truediv__`	Implement the `//` operator.
Method	`all_`	Produce an `_expression.all_` clause against the parent object.
Method	`any_`	Produce an `_expression.any_` clause against the parent object.
Method	`asc`	Produce a `_expression.asc` clause against the parent object.
Method	`between`	Produce a `_expression.between` clause against the parent object, given the lower and upper range.
Method	`collate`	Produce a `_expression.collate` clause against the parent object, given the collation string.
Method	`concat`	Implement the 'concat' operator.
Method	`contains`	Implement the 'contains' operator.
Method	`desc`	Produce a `_expression.desc` clause against the parent object.
Method	`distinct`	Produce a `_expression.distinct` clause against the parent object.
Method	`endswith`	Implement the 'endswith' operator.
Method	`ilike`	Implement the `ilike` operator, e.g. case insensitive LIKE.
Method	`in_`	Implement the `in` operator.
Method	`is_`	Implement the `IS` operator.
Method	`is_distinct_from`	Implement the `IS DISTINCT FROM` operator.
Method	`is_not`	Implement the `IS NOT` operator.
Method	`is_not_distinct_from`	Implement the `IS NOT DISTINCT FROM` operator.
Method	`like`	Implement the `like` operator.
Method	`match`	Implements a database-specific 'match' operator.
Method	`not_ilike`	implement the `NOT ILIKE` operator.
Method	`not_in`	implement the `NOT IN` operator.
Method	`not_like`	implement the `NOT LIKE` operator.
Method	`nulls_first`	Produce a `_expression.nulls_first` clause against the parent object.
Method	`nulls_last`	Produce a `_expression.nulls_last` clause against the parent object.
Method	`regexp_match`	Implements a database-specific 'regexp match' operator.
Method	`regexp_replace`	Implements a database-specific 'regexp replace' operator.
Method	`startswith`	Implement the `startswith` operator.
Class Variable	`timetuple`	Hack, allows datetime objects to be compared on the LHS.

Inherited from Operators (via QueryableAttribute, PropComparator, ColumnOperators):

Method	`__and__`	Implement the `&` operator.
Method	`__invert__`	Implement the `~` operator.
Method	`__or__`	Implement the `\|` operator.
Method	`bool_op`	Return a custom boolean operator.
Method	`op`	Produce a generic operator function.

Inherited from HasCopyInternals (via QueryableAttribute):

Method _copy_internals Reassign internal elements to be clones of themselves.

Inherited from JoinTargetRole (via QueryableAttribute):

Class Variable _role_name Undocumented

Inherited from AllowsLambdaRole (via QueryableAttribute, JoinTargetRole):

Class Variable allows_lambda Undocumented

Inherited from UsesInspection (via QueryableAttribute, JoinTargetRole):

Class Variable	`_post_inspect`	Undocumented
Class Variable	`uses_inspection`	Undocumented

Inherited from SQLRole (via QueryableAttribute, JoinTargetRole, StructuralRole):

Class Variable	`allows_lambda`	Undocumented
Class Variable	`uses_inspection`	Undocumented

Inherited from OnClauseRole (via QueryableAttribute):

Class Variable _role_name Undocumented

Inherited from AllowsLambdaRole (via QueryableAttribute, OnClauseRole):

Class Variable allows_lambda Undocumented

Inherited from SQLRole (via QueryableAttribute, OnClauseRole, StructuralRole):

Class Variable	`allows_lambda`	Undocumented
Class Variable	`uses_inspection`	Undocumented

Inherited from Immutable (via QueryableAttribute):

Method	`_copy_internals`	Undocumented
Method	`params`	Undocumented
Method	`unique_params`	Undocumented
Class Variable	`_is_immutable`	Undocumented

Inherited from MemoizedHasCacheKey (via QueryableAttribute):

Method _generate_cache_key return a cache key.

Inherited from HasCacheKey (via QueryableAttribute, MemoizedHasCacheKey):

Class Variable	`inherit_cache`	Indicate if this `.HasCacheKey` instance should make use of the cache key generation scheme used by its immediate superclass.
Class Method	`_generate_cache_attrs`	generate cache key dispatcher for a new class.
Class Method	`_generate_cache_key_for_object`	Undocumented
Method	`_gen_cache_key`	return an optional cache key.
Class Variable	`__slots__`	Undocumented
Class Variable	`_hierarchy_supports_caching`	private attribute which may be set to False to prevent the inherit_cache warning from being emitted for a hierarchy of subclasses.
Class Variable	`_is_has_cache_key`	Undocumented

def __delete__(self, instance):

overridden in sqlalchemy.orm.attributes.InstrumentedAttribute

Undocumented

def __get__(self, instance, owner):

overridden in sqlalchemy.orm.attributes.InstrumentedAttribute

Undocumented

def __set__(self, instance, value):

overridden in sqlalchemy.orm.attributes.InstrumentedAttribute

Undocumented