Function create_many_to_many_intermediary_model

django/db/models/fields/related.py:1393–1447

(field, klass)

def create_many_to_many_intermediary_model(field, klass):
    from django.db import models

    def set_managed(model, related, through):
        through._meta.managed = model._meta.managed or related._meta.managed

    to_model = resolve_relation(klass, field.remote_field.model)
    name = "%s_%s" % (klass._meta.object_name, field.name)
    lazy_related_operation(set_managed, klass, to_model, name)

    to = make_model_tuple(to_model)[1]
    from_ = klass._meta.model_name
    if to == from_:
        to = "to_%s" % to
        from_ = "from_%s" % from_

    meta = type(
        "Meta",
        (),
        {
            "db_table": field._get_m2m_db_table(klass._meta),
            "auto_created": klass,
            "app_label": klass._meta.app_label,
            "db_tablespace": klass._meta.db_tablespace,
            "unique_together": (from_, to),
            "verbose_name": _("%(from)s-%(to)s relationship")
            % {"from": from_, "to": to},
            "verbose_name_plural": _("%(from)s-%(to)s relationships")
            % {"from": from_, "to": to},
            "apps": field.model._meta.apps,
        },
    )
    # Construct and return the new class.
    return type(
        name,
        (models.Model,),
        {
            "Meta": meta,
            "__module__": klass.__module__,
            from_: models.ForeignKey(
                klass,
                related_name="%s+" % name,
                db_tablespace=field.db_tablespace,
                db_constraint=field.remote_field.db_constraint,
                on_delete=CASCADE,
            ),
            to: models.ForeignKey(
                to_model,
                related_name="%s+" % name,
                db_tablespace=field.db_tablespace,
                db_constraint=field.remote_field.db_constraint,
                on_delete=CASCADE,
            ),
        },
    )


class ManyToManyField(RelatedField):