动态改变数据库连接 Yii

Question

我正在开发一个项目，其中多个网站将从一个 Yii 安装中运行。但每个网站都有自己的数据库，因此数据库连接必须是动态的。

我所做的，我创建了一个 BeginRequestBehavior ，它将在“onBeginRequest”启动。在这里，我将检查哪个 url 已被调用，并确定匹配的数据库（尚未在我的代码中）并创建（或覆盖）“db”组件。

<?php
class BeginRequestBehavior extends CBehavior
{

    /**
     * Attaches the behavior object to the component.
     * @param CComponent the component that this behavior is to be attached to
     * @return void
     */

    public function attach($owner)
    {

        $owner->attachEventHandler('onBeginRequest', array($this, 'switchDatabase'));

    }

    /**
     * Change database based on current url, each website has his own database.
     * Config component 'db' is overwritten with this value
     * @param $event event that is called
     * @return void
     */

    public function switchDatabase($event)
    {
        // Here some logic to check which url has been called..

        $db = Yii::createComponent(array(
            'class' => 'CDbConnection',
            'connectionString' => 'mysql:host=localhost;dbname=test',
            'emulatePrepare' => true,
            'username' => 'secret',
            'password' => 'verysecret',
            'charset' => 'utf8',
            'enableProfiling' => true,
            'enableParamLogging' => true
        ));

        Yii::app()->setComponent('db', $db);

    }
}

它工作正常，但这是正确的方法吗？在其他方法中，我看到人们为他们的模型创建自己的“MyActiveRecord”（扩展 CActiveRecord）并将数据库组件放入属性中。他们为什么这么做？恐怕这种方式会导致数据库连接次数过多。

Answer 1

我使用模型函数来定义她的数据库连接：

public static $conection; // Model attribute

public function getDbConnection(){

    if(self::$conection!==null)
        return self::$conection;

    else{
        self::$conection = Yii::app()->db2; // main.php - DB config name

        if(self::$conection instanceof CDbConnection){
            self::$conection->setActive(true);
            return self::$conection;
        }
        else
            throw new CDbException(Yii::t('yii',"Active Record requires a '$conection' CDbConnection application component."));
    }
}

main.php：

 'db'=>array( 
    'connectionString' => 'mysql:host=192.168.1.*;dbname=database1',
    'emulatePrepare' => true,
    'username' => 'root',
    'password' => 'password',
    'charset' => 'utf8',
    'enableProfiling'=>true,
    'enableParamLogging' => true,
),
'db2'=>array(
    'class'=>'CDbConnection',
    'connectionString' => 'mysql:host=192.168.1.*;dbname=database2',
    'emulatePrepare' => true,
    'username' => 'root',
    'password' => 'password',
    'charset' => 'utf8',
),