django.db.models.fields.related.RelatedField

class documentation

class RelatedField(FieldCacheMixin, Field):

Known subclasses: django.db.models.fields.related.ForeignObject, django.db.models.fields.related.ManyToManyField

Base class that all relational fields inherit from.

Method	`__init__`	Undocumented
Method	`_check_clashes`	Check accessor and reverse query name clashes.
Method	`_check_referencing_to_swapped_model`	Undocumented
Method	`_check_related_name_is_valid`	Undocumented
Method	`_check_related_query_name_is_valid`	Undocumented
Method	`_check_relation_model_exists`	Undocumented
Method	`check`	Undocumented
Method	`contribute_to_class`	Register the field with the model class it belongs to.
Method	`db_type`	Return the database column data type for this field, for the provided connection.
Method	`deconstruct`	Return enough information to recreate the field as a 4-tuple:
Method	`do_related_class`	Undocumented
Method	`formfield`	Pass `limit_choices_to` to the field being constructed.
Method	`get_cache_name`	Undocumented
Method	`get_forward_related_filter`	No summary
Method	`get_limit_choices_to`	Return `limit_choices_to` for this model field.
Method	`get_reverse_related_filter`	No summary
Method	`related_query_name`	Define the name that can be used to identify this related object in a table-spanning query.
Method	`set_attributes_from_rel`	Undocumented
Class Variable	`many_to_many`	Undocumented
Class Variable	`many_to_one`	Undocumented
Class Variable	`one_to_many`	Undocumented
Class Variable	`one_to_one`	Undocumented
Instance Variable	`_limit_choices_to`	Undocumented
Instance Variable	`_related_name`	Undocumented
Instance Variable	`_related_query_name`	Undocumented
Instance Variable	`name`	Undocumented
Instance Variable	`opts`	Undocumented
Instance Variable	`verbose_name`	Undocumented
Property	`related_model`	Undocumented
Property	`swappable_setting`	Get the setting that this is powered from for swapping, or None if it's not swapped in / marked with swappable=False.
Property	`target_field`	When filtering against this relation, return the field on the remote model against which the filtering should happen.

Inherited from FieldCacheMixin:

Method	`delete_cached_value`	Undocumented
Method	`get_cached_value`	Undocumented
Method	`is_cached`	Undocumented
Method	`set_cached_value`	Undocumented

Inherited from Field:

Class Method	`_choices_is_value`	Undocumented
Method	`__copy__`	Undocumented
Method	`__deepcopy__`	Undocumented
Method	`__eq__`	Undocumented
Method	`__hash__`	Undocumented
Method	`__lt__`	Undocumented
Method	`__reduce__`	Pickling should return the model._meta.fields instance of the field, not a new copy of that field. So, use the app registry to load the model and then the field back.
Method	`__repr__`	Display the module, class, and name of the field.
Method	`__str__`	Return "app_label.model_label.field_name" for fields attached to models.
Method	`_check_backend_specific_checks`	Undocumented
Method	`_check_choices`	Undocumented
Method	`_check_db_index`	Undocumented
Method	`_check_deprecation_details`	Undocumented
Method	`_check_field_name`	Check if field name is valid, i.e. 1) does not end with an underscore, 2) does not contain "__" and 3) is not "pk".
Method	`_check_null_allowed_for_primary_keys`	Undocumented
Method	`_check_validators`	Undocumented
Method	`_description`	Undocumented
Method	`_get_flatchoices`	Flattened version of choices tuple.
Method	`cast_db_type`	Return the data type to use in the Cast() function.
Method	`clean`	Convert the value's type and run validation. Validation errors from to_python() and validate() are propagated. Return the correct value if no error is raised.
Method	`clone`	Uses deconstruct() to clone a new copy of this Field. Will not preserve any class attachments/attribute names.
Method	`db_check`	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.
Method	`db_parameters`	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.
Method	`db_type_parameters`	Undocumented
Method	`db_type_suffix`	Undocumented
Method	`get_attname`	Undocumented
Method	`get_attname_column`	Undocumented
Method	`get_choices`	Return choices with a default blank choices included, for use as <select> choices for this field.
Method	`get_col`	Undocumented
Method	`get_db_converters`	Undocumented
Method	`get_db_prep_save`	Return field's value prepared for saving into a database.
Method	`get_db_prep_value`	Return field's value prepared for interacting with the database backend.
Method	`get_default`	Return the default value for this field.
Method	`get_filter_kwargs_for_object`	Return a dict that when passed as kwargs to self.model.filter(), would yield all instances having the same value for this field as obj has.
Method	`get_internal_type`	Undocumented
Method	`get_pk_value_on_save`	No summary
Method	`get_prep_value`	Perform preliminary non-db specific value checks and conversions.
Method	`has_default`	Return a boolean of whether this field has a default value.
Method	`pre_save`	Return field's value just before saving.
Method	`rel_db_type`	Return the data type that a related field pointing to this field should use. For example, this method is called by ForeignKey and OneToOneField to determine its data type.
Method	`run_validators`	Undocumented
Method	`save_form_data`	Undocumented
Method	`select_format`	Custom format for select clauses. For example, GIS columns need to be selected as AsText(table.col) on MySQL as the table.col data can't be used by Django.
Method	`set_attributes_from_name`	Undocumented
Method	`to_python`	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.
Method	`validate`	Validate value and raise ValidationError if necessary. Subclasses should override this to provide validation logic.
Method	`value_from_object`	Return the value of this field in the given model instance.
Method	`value_to_string`	Return a string value of this field from the passed obj. This is used by the serialization framework.
Class Variable	`auto_creation_counter`	Undocumented
Class Variable	`default_error_messages`	Undocumented
Class Variable	`default_validators`	Undocumented
Class Variable	`description`	Undocumented
Class Variable	`empty_strings_allowed`	Undocumented
Class Variable	`empty_values`	Undocumented
Class Variable	`flatchoices`	Undocumented
Class Variable	`hidden`	Undocumented
Class Variable	`system_check_deprecated_details`	Undocumented
Class Variable	`system_check_removed_details`	Undocumented
Instance Variable	`_db_tablespace`	Undocumented
Instance Variable	`_error_messages`	Undocumented
Instance Variable	`_unique`	Undocumented
Instance Variable	`_validators`	Undocumented
Instance Variable	`_verbose_name`	Undocumented
Instance Variable	`attname`	Undocumented
Instance Variable	`auto_created`	Undocumented
Instance Variable	`blank`	Undocumented
Instance Variable	`choices`	Undocumented
Instance Variable	`column`	Undocumented
Instance Variable	`concrete`	Undocumented
Instance Variable	`creation_counter`	Undocumented
Instance Variable	`db_column`	Undocumented
Instance Variable	`db_index`	Undocumented
Instance Variable	`default`	Undocumented
Instance Variable	`editable`	Undocumented
Instance Variable	`error_messages`	Undocumented
Instance Variable	`help_text`	Undocumented
Instance Variable	`is_relation`	Undocumented
Instance Variable	`max_length`	Undocumented
Instance Variable	`model`	Undocumented
Instance Variable	`null`	Undocumented
Instance Variable	`primary_key`	Undocumented
Instance Variable	`remote_field`	Undocumented
Instance Variable	`serialize`	Undocumented
Instance Variable	`unique_for_date`	Undocumented
Instance Variable	`unique_for_month`	Undocumented
Instance Variable	`unique_for_year`	Undocumented
Property	`_get_default`	Undocumented
Property	`cached_col`	Undocumented
Property	`db_returning`	Private API intended only to be used by Django itself. Currently only the PostgreSQL backend supports returning multiple fields on a model.
Property	`db_tablespace`	Undocumented
Property	`unique`	Undocumented
Property	`validators`	Some validators can't be created at field initialization time. This method provides a way to delay their creation until required.

Inherited from RegisterLookupMixin (via Field):

Class Method	`get_lookups`	Undocumented
Class Method	`register_lookup`	Undocumented
Static Method	`merge_dicts`	Merge dicts in reverse to preference the order of the original list. e.g., merge_dicts([a, b]) will preference the keys in 'a' over those in 'b'.
Class Method	`_clear_cached_lookups`	Undocumented
Class Method	`_get_lookup`	Undocumented
Class Method	`_unregister_lookup`	Remove given lookup from cls lookups. For use in tests only as it's not thread-safe.
Method	`get_lookup`	Undocumented
Method	`get_transform`	Undocumented

def __init__(self, related_name=None, related_query_name=None, limit_choices_to=None, **kwargs):

overrides django.db.models.fields.Field.__init__

overridden in django.db.models.fields.related.ForeignObject, django.db.models.fields.related.ManyToManyField

Undocumented

def _check_clashes(self):

Check accessor and reverse query name clashes.

def _check_referencing_to_swapped_model(self):

Undocumented

def _check_related_name_is_valid(self):

Undocumented

def _check_related_query_name_is_valid(self):

Undocumented

def _check_relation_model_exists(self):

Undocumented

def check(self, **kwargs):

overrides django.db.models.fields.Field.check

overridden in django.db.models.fields.related.ForeignObject, django.db.models.fields.related.ManyToManyField

Undocumented

def contribute_to_class(self, cls, name, private_only=False, **kwargs):

overrides django.db.models.fields.Field.contribute_to_class

overridden in django.db.models.fields.related.ForeignObject, django.db.models.fields.related.ManyToManyField

If private_only is True, create a separate instance of this field for every subclass of cls, even if cls is not an abstract model.

def db_type(self, connection):

overrides django.db.models.fields.Field.db_type

overridden in django.db.models.fields.related.ForeignKey, django.db.models.fields.related.ManyToManyField

Return the database column data type for this field, for the provided connection.

def deconstruct(self):

overrides django.db.models.fields.Field.deconstruct

overridden in django.db.models.fields.related.ForeignObject, django.db.models.fields.related.ManyToManyField

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

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.

def do_related_class(self, other, cls):

Undocumented

def formfield(self, **kwargs):

overrides django.db.models.fields.Field.formfield

overridden in django.db.models.fields.related.ForeignKey, django.db.models.fields.related.ManyToManyField

Pass limit_choices_to to the field being constructed.

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.

def get_cache_name(self):

overrides django.db.models.fields.mixins.FieldCacheMixin.get_cache_name

Undocumented

def get_forward_related_filter(self, obj):

Return the keyword arguments that when supplied to self.model.object.filter(), would select all instances related through this field to the remote obj. This is used to build the querysets returned by related descriptors. obj is an instance of self.related_field.model.

def get_limit_choices_to(self):

Return limit_choices_to for this model field.

If it is a callable, it will be invoked and the result will be returned.

def get_reverse_related_filter(self, obj):

Complement to get_forward_related_filter(). Return the keyword arguments that when passed to self.related_field.model.object.filter() select all instances of self.related_field.model related through this field to obj. obj is an instance of self.model.

def related_query_name(self):

Define the name that can be used to identify this related object in a table-spanning query.

def set_attributes_from_rel(self):

overridden in django.db.models.fields.related.ManyToManyField

Undocumented

many_to_many: bool =

overrides django.db.models.fields.Field.many_to_many

overridden in django.db.models.fields.related.ForeignObject, django.db.models.fields.related.ManyToManyField

Undocumented

many_to_one: bool =

overrides django.db.models.fields.Field.many_to_one

overridden in django.db.models.fields.related.ForeignObject, django.db.models.fields.related.ManyToManyField

Undocumented

one_to_many: bool =

overrides django.db.models.fields.Field.one_to_many

overridden in django.db.models.fields.related.ForeignObject, django.db.models.fields.related.ManyToManyField

Undocumented

one_to_one: bool =

overrides django.db.models.fields.Field.one_to_one

overridden in django.db.models.fields.related.ForeignObject, django.db.models.fields.related.ManyToManyField

Undocumented

_limit_choices_to =

Undocumented

_related_name =

Undocumented

_related_query_name =

Undocumented

name =

overrides django.db.models.fields.Field.name

Undocumented

opts =

Undocumented

verbose_name =

overrides django.db.models.fields.Field.verbose_name

Undocumented

@cached_property
related_model =

overrides django.db.models.fields.Field.related_model

Undocumented

@property
swappable_setting =

Get the setting that this is powered from for swapping, or None if it's not swapped in / marked with swappable=False.

@property
target_field =

overridden in django.db.models.fields.related.ForeignKey

When filtering against this relation, return the field on the remote model against which the filtering should happen.