'Given a column type (e.g. \'BLOB\', \'VARCHAR\'), and an internal type
(e.g. \'GenericIPAddressField\'), returns the SQL necessary to cast it
before using it in a WHERE statement. Note that the resulting string
should contain a \'%s\' placeholder for the column being searched against.'

def field_cast_sql(self, db_type, internal_type):

    return '%s'
