Class ManyToManyField

django.db.models.fields.related.ManyToManyField

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

Declaration

class ManyToManyField(RelatedField)

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Documentation

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

Methods

▶ def __init__(self, to, related_name=None, related_query_name=None, limit_choices_to=None, ...) override
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,
)
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This method overrides django.db.models.fields.Field.__init__.
▶ def check(self, **kwargs) override
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This method overrides django.db.models.fields.related.RelatedField.check.
▶ def contribute_to_class(self, cls, name, **kwargs) override
inherited doc Register the field with the model class it belongs to.
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This method 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)
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▶ 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.
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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.
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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:

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This method overrides django.db.models.fields.related.RelatedField.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.

▶ 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.
```
▷ def get_path_info(self, filtered_relation=None)
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▷ def get_reverse_path_info(self, filtered_relation=None)
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▶ def save_form_data(self, instance, data) override
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This method overrides django.db.models.fields.Field.save_form_data.
▶ def set_attributes_from_rel(self) override
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This method overrides django.db.models.fields.related.RelatedField.set_attributes_from_rel.
▶ def value_from_object(self, obj) override
inherited doc Return the value of this field in the given model instance.
source link
This method overrides django.db.models.fields.Field.value_from_object.

Inherited methods

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, swappable_setting, target_field
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_attname, get_attname_column, get_choices, get_col, get_db_converters, get_db_prep_save, get_db_prep_value, get_default, get_filter_kwargs_for_object, get_internal_type, get_pk_value_on_save, get_prep_value, has_default, pre_save, rel_db_type, run_validators, select_format, set_attributes_from_name, to_python, unique, validate, validators, value_to_string
Methods inherited from django.db.models.query_utils.RegisterLookupMixin:
get_lookup, get_lookups, get_transform, merge_dicts, register_lookup

Reexports