Class ForeignKey

django.db.models.fields.related.ForeignKey

Provide a many-to-one relation by adding a column to the local model to hold the remote value.

Declaration

Documentation

By default ForeignKey will target the pk of the remote model but this
behavior can be changed by using the ``to_field`` argument.

Methods

▶ def __init__(self, to, on_delete, related_name=None, related_query_name=None, ...) override
def __init__(
self,
to,
on_delete,
related_name=None,
related_query_name=None,
limit_choices_to=None,
parent_link=False,
to_field=None,
db_constraint=True,
**kwargs,
)
source link
This method overrides django.db.models.fields.related.ForeignObject.__init__.
Overrides
This method is overriden in:
- django.db.models.fields.related.OneToOneField
▶ def check(self, **kwargs) override
source link
This method overrides django.db.models.fields.related.ForeignObject.check.
▶ def contribute_to_related_class(self, cls, related) override
source link
This method overrides django.db.models.fields.related.ForeignObject.contribute_to_related_class.
▷ def convert_empty_strings(self, value, expression, connection)
source link
▶ def db_check(self, connection) override
inherited doc Return the database column check constraint for this field, for the provided connection. Works the same way as db_type() for the case that get_internal_type() does not map to a preexisting model field.
source link
This method overrides django.db.models.fields.Field.db_check.
▶ def db_parameters(self, connection) override
inherited doc Extension of db_type(), providing a range of different return values (type, checks). This will look at db_type(), allowing custom model fields to override it.
source link
This method overrides django.db.models.fields.Field.db_parameters.
▶ def db_type(self, connection) override
inherited doc Return the database column data type for this field, for the provided connection.
source link
This method overrides django.db.models.fields.related.RelatedField.db_type.

▶ def deconstruct(self) override

inherited doc Return enough information to recreate the field as a 4-tuple:

source link

This method overrides django.db.models.fields.related.ForeignObject.deconstruct.

* The name of the field on the model, if contribute_to_class() has
   been run.
 * The import path of the field, including the class:e.g.
   django.db.models.IntegerField This should be the most portable
   version, so less specific may be better.
 * A list of positional arguments.
 * A dict of keyword arguments.

Note that the positional or keyword arguments must contain values of
the following types (including inner values of collection types):

 * None, bool, str, int, float, complex, set, frozenset, list, tuple,
   dict
 * UUID
 * datetime.datetime (naive), datetime.date
 * top-level classes, top-level functions - will be referenced by their
   full import path
 * Storage instances - these have their own deconstruct() method

This is because the values here must be serialized into a text format
(possibly new Python code, possibly JSON) and these are the only types
with encoding handlers defined.

There's no need to return the exact way the field was instantiated this
time, just ensure that the resulting field is the same - prefer keyword
arguments over positional ones, and omit parameters with their default
values.

Overrides

This method is overriden in:

django.db.models.fields.related.OneToOneField

▶ def formfield(self, *, using=None, **kwargs) override
inherited doc Pass ``limit_choices_to`` to the field being constructed.
source link
This method overrides django.db.models.fields.related.RelatedField.formfield.
```
Only passes it if there is a type that supports related fields.
This is a similar strategy used to pass the ``queryset`` to the field
being constructed.
```
Overrides
This method is overriden in:
- django.db.models.fields.related.OneToOneField
▶ def get_attname(self) override
source link
This method overrides django.db.models.fields.Field.get_attname.
▶ def get_attname_column(self) override
source link
This method overrides django.db.models.fields.related.ForeignObject.get_attname_column.
▶ def get_col(self, alias, output_field=None) override
source link
This method overrides django.db.models.fields.Field.get_col.
▶ def get_db_converters(self, connection) override
source link
This method overrides django.db.models.fields.Field.get_db_converters.
▶ def get_db_prep_save(self, value, connection) override
inherited doc Return field's value prepared for saving into a database.
source link
This method overrides django.db.models.fields.Field.get_db_prep_save.
▶ def get_db_prep_value(self, value, connection, prepared=False) override
inherited doc Return field's value prepared for interacting with the database backend.
source link
This method overrides django.db.models.fields.Field.get_db_prep_value.
```
Used by the default implementations of get_db_prep_save().
```
▶ def get_default(self) override
Return the to_field if the default value is an object.
source link
This method overrides django.db.models.fields.Field.get_default.
▶ def get_prep_value(self, value) override
inherited doc Perform preliminary non-db specific value checks and conversions.
source link
This method overrides django.db.models.fields.Field.get_prep_value.
▶ def get_reverse_path_info(self, filtered_relation=None) override
Get path from the related model to this field's model.
source link
This method overrides django.db.models.fields.related.ForeignObject.get_reverse_path_info.
▶ def resolve_related_fields(self) override
source link
This method overrides django.db.models.fields.related.ForeignObject.resolve_related_fields.
▶ def target_field(self) override @property
inherited doc When filtering against this relation, return the field on the remote model against which the filtering should happen.
@property
def target_field(self)
source link
This method overrides django.db.models.fields.related.RelatedField.target_field.
▶ def to_python(self, value) override
inherited doc Convert the input value into the expected Python data type, raising django.core.exceptions.ValidationError if the data can't be converted. Return the converted value. Subclasses should override this.
source link
This method overrides django.db.models.fields.Field.to_python.
▶ def validate(self, value, model_instance) override
inherited doc Validate value and raise ValidationError if necessary. Subclasses should override this to provide validation logic.
source link
This method overrides django.db.models.fields.Field.validate.

Inherited methods

Methods inherited from django.db.models.fields.related.ForeignObject:
contribute_to_class, foreign_related_fields, get_extra_descriptor_filter, get_extra_restriction, get_foreign_related_value, get_instance_value_for_fields, get_joining_columns, get_local_related_value, get_lookups, get_path_info, get_reverse_joining_columns, local_related_fields, related_fields, reverse_related_fields
Methods inherited from django.db.models.fields.related.RelatedField:
do_related_class, get_cache_name, get_forward_related_filter, get_limit_choices_to, get_reverse_related_filter, related_model, related_query_name, set_attributes_from_rel, swappable_setting
Methods inherited from django.db.models.fields.mixins.FieldCacheMixin:
delete_cached_value, get_cached_value, is_cached, set_cached_value
Methods inherited from django.db.models.fields.Field:
__copy__, __deepcopy__, __eq__, __hash__, __lt__, __reduce__, __repr__, __str__, cached_col, cast_db_type, clean, clone, db_returning, db_tablespace, db_type_parameters, db_type_suffix, get_choices, get_filter_kwargs_for_object, get_internal_type, get_pk_value_on_save, has_default, pre_save, rel_db_type, run_validators, save_form_data, select_format, set_attributes_from_name, unique, validators, value_from_object, value_to_string
Methods inherited from django.db.models.query_utils.RegisterLookupMixin:
get_lookup, get_transform, merge_dicts, register_lookup

Subclasses

django.db.models.fields.related.OneToOneField

Reexports

Imported in django.db.models.

Django

Class ForeignKey

Declaration

Documentation

Methods

Overrides

Overrides

Overrides

Inherited methods

Subclasses

Reexports