function _DropAutoIncrement($tabname)
	{
		$tabname = $this->connection->quote('%'.$tabname.'%');

		$seq = $this->connection->GetOne("SELECT relname FROM pg_class WHERE NOT relname ~ 'pg_.*' AND relname LIKE $tabname AND relkind='S'");

		// check if a tables depends on the sequenz and it therefor cant and dont need to be droped separatly
		if (!$seq || $this->connection->GetOne("SELECT relname FROM pg_class JOIN pg_depend ON pg_class.relfilenode=pg_depend.objid WHERE relname='$seq' AND relkind='S' AND deptype='i'")) {
			return False;
		}
		return "DROP SEQUENCE ".$seq;
	}