动态改变数据库连接 Yii

Question

我正在开展一个项目，该项目将通过一个 Yii 安装运行多个网站。但是每个网站都有自己的数据库，所以数据库连接必须是动态的。

我做了什么，我创建了一个 BeginRequestBehavior，它将在“onBeginRequest”中启动。在这里，我将检查调用了哪个 url 并确定匹配的数据库（不在我的代码中）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 db 组件放在一个属性中。他们为什么这样做？恐怕这样连接数据库的次数会超出必要的次数。

Answer 1

我使用 model 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."));
    }
}

ma​​in.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',
),

Answer 2

使用 yii 时使用多个数据库连接的更酷的方式：

换句话说，您需要 1 个主数据库来存储用户配置文件和一个数据库连接；

对于其他从属数据库，您需要一个单独的设置；您将在需要时切换数据库连接。我使用用户 ID 在我的示例中切换它。

我使用 gii 生成了从属数据库表的模型，我认为所有从属数据库都具有相同的表结构，并且在该模型之上，我使用另一个类，如下所示；

    'db' => array(
        'class' => 'PortalDbConnection',
        'connectionString' => 'mysql:host=localhost;dbname=mydb',
        'username' => 'dev',
        'password' => '123456',
        'tablePrefix' => '',
        'emulatePrepare' => true,
        'enableParamLogging' => true,
        'enableProfiling' => true,
        'charset' => 'utf8',
    ),
    'dbx' => array(
        'connectionString' => 'mysql:host=localhost;dbname=mydb1',
        'username' => 'dev',
        'password' => '123456',
        'charset' => 'utf8',
        'tablePrefix' => '',
        'autoConnect' => false,
        'class' => 'CDbConnection', //this may be the reason you get errors! always set this
    ),

现在，您的模型的 php 代码：

<?php

class DomainSlaveM extends Domain {

    public static function model($className = __CLASS__) {
        return parent::model($className);
    }

    public static $server_id = 1;
    public static $slave_db;

public function getDbConnection() {
    self::$slave_db = Yii::app()->dbx;
    if (self::$slave_db instanceof CDbConnection) {
        self::$slave_db->active = false;
        $config = require(Yii::app()->getBasePath() . '/config/location/flavius.php');
        $connectionString = $config['components']['dbx']['connectionString'];
        self::$slave_db->connectionString = sprintf($connectionString, self::$server_id);
        self::$slave_db->setActive(true);
        return self::$slave_db;
    }
    else
        throw new CDbException(Yii::t('yii', 'Active Record requires a "db" CDbConnection application component.'));
}

    }

并像这样使用它：

    public function createDomainSlaveM($model) {
//switch the db connection; $server_id gets values, from 1 to N
            DomainSlaveM::$server_id = $model->user_id;
            $model_domain_slave_m = new DomainSlaveM();
            $model_domain_slave_m->attributes = $model->attributes;
            if ($model_domain_slave_m->validate() && $model_domain_slave_m->save()) {
                //ok
            } else {
                //bad
            }
        }