Generates an identifier from a list of column names obeying a certain string length.

def _generate_identifier_name(self, columns, prefix="", max_size=30):
        """
        Generates an identifier from a list of column names obeying a certain string length.
        """
        hash = ""
        for column in columns:
            hash += "%x" % binascii.crc32(encode(str(column)))

        return (prefix + "_" + hash)[:max_size]