def _constraint_names(self, model, column_names=None, unique=None,
                          primary_key=None, index=None, foreign_key=None,
                          check=None):
        """
        Returns all constraint names matching the columns and conditions
        """
        column_names = list(column_names) if column_names else None
        with self.connection.cursor() as cursor:
            constraints = get_constraints(cursor, model._meta.db_table)
        result = []
        for name, infodict in constraints.items():
            if column_names is None or column_names == infodict['columns']:
                if unique is not None and infodict['unique'] != unique:
                    continue
                if primary_key is not None and infodict['primary_key'] != primary_key:
                    continue
                if index is not None and infodict['index'] != index:
                    continue
                if check is not None and infodict['check'] != check:
                    continue
                if foreign_key is not None and not infodict['foreign_key']:
                    continue
                result.append(name)

        return result
Returns all constraint names matching the columns and conditions