Field attribute reference

Every Field instance contains several attributes that allow introspecting its behavior. Use these attributes instead of isinstance checks when you need to write code that depends on a field's functionality. These attributes can be used together with the Model._meta API to narrow down a search for specific field types. Custom model fields should implement these flags.

Attributes for fields

Field.auto_created

Boolean flag that indicates if the field was automatically created, such as the OneToOneField used by model inheritance.

Field.concrete

Boolean flag that indicates if the field has a database column associated with it.

Field.hidden

Boolean flag that indicates if a field is used to back another non-hidden field's functionality (for example, the content_type and object_id fields that make up a GenericForeignKey). The hidden flag is used to distinguish what constitutes the public subset of fields on the model from all the fields on the model.

Field.is_relation

Boolean flag that indicates if a field contains references to one or more other models for its functionality (for example, ForeignKey, ManyToManyField, OneToOneField, and others).

Field.model

Returns the model on which the field is defined. If a field is defined on a superclass of a model, model will refer to the superclass, not the class of the instance.

Attributes for fields with relations

These attributes are used to query for the cardinality and other details of a relation. These attribute are present on all fields; however, they will only have meaningful values if the field is a relation type (Field.is_relation=True).

Field.many_to_many

Boolean flag that is True if the field has a many-to-many relation; False otherwise. The only field included with Django where this is True is ManyToManyField.

Field.many_to_one

Boolean flag that is True if the field has a many-to-one relation, such as a ForeignKey; False otherwise.

Field.one_to_many

Boolean flag that is True if the field has a one-to-many relation, such as a GenericRelation or the reverse of a ForeignKey; False otherwise.

Field.one_to_one

Boolean flag that is True if the field has a one-to-one relation, such as a OneToOneField; False otherwise.

Field.related_model

Points to the model the field relates to. For example, Author in ForeignKey(Author). If a field has a generic relation (such as a GenericForeignKey or a GenericRelation) then related_model will be None.