protected function createSessionTable($db,$tableName)
	{
		switch($db->getDriverName())
		{
			case 'mysql':
				$blob='LONGBLOB';
				break;
			case 'pgsql':
				$blob='BYTEA';
				break;
			case 'sqlsrv':
			case 'mssql':
			case 'dblib':
				$blob='VARBINARY(MAX)';
				break;
			default:
				$blob='BLOB';
				break;
		}
		$db->createCommand()->createTable($tableName,array(
			'id'=>'CHAR(32) PRIMARY KEY',
			'expire'=>'integer',
			'data'=>$blob,
		));
	}