django.db.models.fields.related.ManyToManyField

class documentation

class ManyToManyField(RelatedField):

Provide a many-to-many relation by using an intermediary model that holds two ForeignKey fields pointed at the two sides of the relation.

Unless a through model was provided, ManyToManyField will use the create_many_to_many_intermediary_model factory to automatically generate the intermediary model.

Method	`__init__`	Undocumented
Method	`_check_ignored_options`	Undocumented
Method	`_check_relationship_model`	Undocumented
Method	`_check_table_uniqueness`	Undocumented
Method	`_check_unique`	Undocumented
Method	`_get_m2m_attr`	Function that can be curried to provide the source accessor or DB column name for the m2m table.
Method	`_get_m2m_db_table`	Function that can be curried to provide the m2m table name for this relation.
Method	`_get_m2m_reverse_attr`	Function that can be curried to provide the related accessor or DB column name for the m2m table.
Method	`_get_path_info`	Called by both direct and indirect m2m traversal.
Method	`check`	Undocumented
Method	`contribute_to_class`	Register the field with the model class it belongs to.
Method	`contribute_to_related_class`	Undocumented
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`	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	`formfield`	Pass `limit_choices_to` to the field being constructed.
Method	`get_path_info`	Undocumented
Method	`get_reverse_path_info`	Undocumented
Method	`save_form_data`	Undocumented
Method	`set_attributes_from_rel`	Undocumented
Method	`value_from_object`	Return the value of this field in the given model instance.
Class Variable	`description`	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	`db_table`	Undocumented
Instance Variable	`has_null_arg`	Undocumented
Instance Variable	`m2m_column_name`	Undocumented
Instance Variable	`m2m_db_table`	Undocumented
Instance Variable	`m2m_field_name`	Undocumented
Instance Variable	`m2m_reverse_field_name`	Undocumented
Instance Variable	`m2m_reverse_name`	Undocumented
Instance Variable	`m2m_reverse_target_field_name`	Undocumented
Instance Variable	`m2m_target_field_name`	Undocumented
Instance Variable	`swappable`	Undocumented

Inherited from RelatedField:

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	`do_related_class`	Undocumented
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.
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 (via RelatedField):

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

Inherited from Field (via RelatedField):

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_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	`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_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	`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 RelatedField, 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, to, related_name=None, related_query_name=None, limit_choices_to=None, symmetrical=None, through=None, through_fields=None, db_constraint=True, db_table=None, swappable=True, **kwargs):

overrides django.db.models.fields.related.RelatedField.__init__

Undocumented

def _check_ignored_options(self, **kwargs):

Undocumented

def _check_relationship_model(self, from_model=None, **kwargs):

Undocumented

def _check_table_uniqueness(self, **kwargs):

Undocumented

def _check_unique(self, **kwargs):

Undocumented

def _get_m2m_attr(self, related, attr):

Function that can be curried to provide the source accessor or DB column name for the m2m table.

def _get_m2m_db_table(self, opts):

Function that can be curried to provide the m2m table name for this relation.

def _get_m2m_reverse_attr(self, related, attr):

Function that can be curried to provide the related accessor or DB column name for the m2m table.

def _get_path_info(self, direct=False, filtered_relation=None):

Called by both direct and indirect m2m traversal.

def check(self, **kwargs):

overrides django.db.models.fields.related.RelatedField.check

Undocumented

def contribute_to_class(self, cls, name, **kwargs):

overrides django.db.models.fields.related.RelatedField.contribute_to_class

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 contribute_to_related_class(self, cls, related):

Undocumented

def db_check(self, connection):

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

def db_parameters(self, connection):

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

def db_type(self, connection):

overrides django.db.models.fields.related.RelatedField.db_type

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

def deconstruct(self):

overrides django.db.models.fields.related.RelatedField.deconstruct

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 formfield(self, *, using=None, **kwargs):

overrides django.db.models.fields.related.RelatedField.formfield

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_path_info(self, filtered_relation=None):

Undocumented

def get_reverse_path_info(self, filtered_relation=None):

Undocumented

def save_form_data(self, instance, data):

overrides django.db.models.fields.Field.save_form_data

Undocumented

def set_attributes_from_rel(self):

overrides django.db.models.fields.related.RelatedField.set_attributes_from_rel

Undocumented

def value_from_object(self, obj):

overrides django.db.models.fields.Field.value_from_object

Return the value of this field in the given model instance.

description =

overrides django.db.models.fields.Field.description

Undocumented

many_to_many: bool =

overrides django.db.models.fields.related.RelatedField.many_to_many

Undocumented

many_to_one: bool =

overrides django.db.models.fields.related.RelatedField.many_to_one

Undocumented

one_to_many: bool =

overrides django.db.models.fields.related.RelatedField.one_to_many

Undocumented

one_to_one: bool =

overrides django.db.models.fields.related.RelatedField.one_to_one

Undocumented

db_table =

Undocumented

has_null_arg =

Undocumented

m2m_column_name =

Undocumented

m2m_db_table =

Undocumented

m2m_field_name =

Undocumented

m2m_reverse_field_name =

Undocumented

m2m_reverse_name =

Undocumented

m2m_reverse_target_field_name =

Undocumented

m2m_target_field_name =

Undocumented

swappable =

Undocumented