peewee_moves.py 文件源码

def foreign_key(self, coltype, name, references, **kwargs):
        """
        Add a foreign key to the model.
        This has some special cases, which is why it's not handled like all the other column types.

        :param name: Name of the foreign key.
        :param references: Table name in the format of "table.column" or just
            "table" (and id will be default column).
        :param kwargs: Additional kwargs to pass to the column instance.
            You can also provide "on_delete" and "on_update" to add constraints.
        :return: None
        """
        try:
            rel_table, rel_column = references.split('.', 1)
        except ValueError:
            rel_table, rel_column = references, 'id'

        # Create a dummy model that we can relate this field to.
        # Add the foreign key as a local field on the dummy model.
        # We only do this so that Peewee can generate the nice foreign key constraint for us.

        class DummyRelated(peewee.Model):
            class Meta:
                primary_key = False
                database = peewee.Proxy()
                db_table = rel_table

        rel_field_class = FIELD_TO_PEEWEE.get(coltype, peewee.IntegerField)
        rel_field = rel_field_class()
        rel_field.add_to_class(DummyRelated, rel_column)

        field = peewee.ForeignKeyField(DummyRelated, db_column=name, to_field=rel_column, **kwargs)
        field.add_to_class(self.model, name)