PHP，用于处理 MySql 和 mysql_close 问题的简单类

Question

这是一个用于处理数据库的简单 php 类。此类的问题在于 __destruct 方法，该方法启动 mysql_close 函数。如果我创建两个位于代码中非常接近的数据库对象，则会导致错误。看起来 mysql_close 关闭了所有数据库连接，而不仅仅是他自己的($this->dbLink)。为什么会这样？

    require_once("modules/required/OptionsReader/m_OptionsReader.php");

    class DB{
        private $dbLink;

        public function  __construct() {
            $options = new OptionsReader();
            $DBSettings = $options->getDBSettings();
            $this->dbLink = mysql_connect($DBSettings->getAddress(),$DBSettings->getUserName(),$DBSettings->getPswd());
            @mysql_select_db($DBSettings->getDBName()) or die( "Unable to select database");
            mysql_query( "set names 'utf8'" );
        }

        public function  __destruct() {
            mysql_close($this->dbLink);
        }


        public function launchQuery($query){
            return mysql_query($query);
        }
    }
?>

附言我知道这个问题的简单解决方案就是从 __desctuctor close() 函数创建并手动启动它，但了解发生了什么会很棒。谢谢

Answer 1

@zneak 是正确的。 mysql_connect 执行池连接。问题是，为什么要关闭连接呢？在我多年的 PHP 开发中，我用过 mysql_connect 的次数一只手都能数过来，我几乎只用过 mysql_pconnect

来自 http://php.net/mysql_pconnect —

Establishes a persistent connection to a MySQL server.

mysql_pconnect() acts very much like mysql_connect() with two major differences.

First, when connecting, the function would first try to find a (persistent) link that's already open with the same host, username and password. If one is found, an identifier for it will be returned instead of opening a new connection.

Second, the connection to the SQL server will not be closed when the execution of the script ends. Instead, the link will remain open for future use (mysql_close() will not close links established by mysql_pconnect()).