public static function Create($configname = 'db') { //避免重复创建连接 global $G_X; if ($G_X[$configname]['dbtype'] == 'mssql') { $sqltype = 'Pdo_Mssql'; } else { $sqltype = 'Pdo_Mysql'; } if (null === self::$dbCfg) { self::$dbCfg = $configname; } //if (null === self::$db) {self::$db = new Pdo_Mysql($G_X[self::$dbCfg]);} if ($configname !== self::$dbCfg) { self::$dbCfg = $configname; self::$db = new $sqltype($G_X[self::$dbCfg]); } elseif (null === self::$db) { self::$db = new $sqltype($G_X[self::$dbCfg]); } return self::$db; }