Set up the subdomain db's tables

def _create_tables(self):
        """
        Set up the subdomain db's tables
        """
        cursor = self.conn.cursor()

        create_cmd = """CREATE TABLE IF NOT EXISTS {} (
        fully_qualified_subdomain TEXT NOT NULL,
        domain TEXT NOT NULL,
        sequence INTEGER NOT NULL,
        owner TEXT NOT NULL,
        zonefile_hash TEXT NOT NULL,
        signature TEXT NOT NULL,
        block_height INTEGER NOT NULL,
        parent_zonefile_hash TEXT NOT NULL,
        parent_zonefile_index INTEGER NOT NULL,
        zonefile_offset INTEGER NOT NULL,
        txid TEXT NOT NULL,
        missing TEXT NOT NULL,
        accepted INTEGER NOT NULL,
        resolver TEXT,
        PRIMARY KEY(fully_qualified_subdomain,parent_zonefile_index));
        """.format(self.subdomain_table)
        db_query_execute(cursor, create_cmd, ())

        # set up a queue as well
        queue_con = queuedb_open(self.queue_path)
        queue_con.close()