PHP实战：Yii实现MySQL多数据库和读写分离实例分析

<?php
return array(
'passport' => array(
'write' => array(
'class' => 'CDbConnection',
'connectionString' => 'mysql:host=10.1.39.2;dbname=db1′,
'emulatePrepare' => true,
//'enableParamLogging' => true,
'enableProfiling' => true,
'username' => 'root',
'password' => '',
'charset' => 'utf8′,
'schemaCachingDuration'=>3600,
),
'read' => array(
array(
'class' => 'CDbConnection',
'connectionString' => 'mysql:host=10.1.39.3;dbname=db1,
'emulatePrepare' => true,
//'enableParamLogging' => true,
'enableProfiling' => true,
'username' => 'root',
'password' => '',
'charset' => 'utf8′,
'schemaCachingDuration'=>3600,
),
array(
'class' => 'CDbConnection',
'connectionString' => 'mysql:host=10.1.39.4;dbname=db3′,
'emulatePrepare' => true,
//'enableParamLogging' => true,
'enableProfiling' => true,
'username' => 'root',
'password' => '',
'charset' => 'utf8′,
'schemaCachingDuration'=>3600,
),
),
),
);

<?php
return array(
//key为数据库名称,value为Model
'passport' => array('User','Post'),
'microblog' => array('…'),
);
?>

/**
* 基于CActiveRecord类的封装,实现多库和主从读写分离
* 所有Model都必须继承些类.
*
*/
class ActiveRecord extends CActiveRecord
{
//model配置
public $modelConfig = '';
//数据库配置
public $dbConfig = '';
//定义一个多数据库集合
static $dataBase = array();
//当前数据库名称
public $dbName = '';
//定义库类型(读或写)
public $dbType = 'read'; //'read' or 'write'
/**
* 在原有基础上添加了一个dbname参数
* @param string $scenario Model的应用场景
* @param string $dbname 数据库名称
*/
public function __construct($scenario='insert', $dbname = '')
{
if (!empty($dbname))
$this->dbName = $dbname;
parent::__construct($scenario);
}
/**
* 重写父类的getDbConnection办法
* 多库和主从都在这里切换
*/
public function getDbConnection()
{
//如果指定的数据库对象存在则直接返回
if (self::$dataBase[$this->dbName]!==null)
return self::$dataBase[$this->dbName];
if ($this->dbName == 'db'){
self::$dataBase[$this->dbName] = Yii::app()->getDb();
}else{
$this->changeConn($this->dbType);
}
if(self::$dataBase[$this->dbName] instanceof CDbConnection){
self::$dataBase[$this->dbName]->setActive(true);
return self::$dataBase[$this->dbName];
} else
throw new CDbException(Yii::t('yii','Model requires a "db" CDbConnection application component.'));
}
/**
* 获取配置文件
* @param unknown_type $type
* @param unknown_type $key
*/
private function getConfig($type="modelConfig",$key="){
$config = Yii::app()->params[$type];
if($key)
$config = $config[$key];
return $config;
}
/**
* 获取数据库名称
*/
private function getDbName(){
if($this->dbName)
return $this->dbName;
$modelName = get_class($this->model());
$this->modelConfig = $this->getConfig('modelConfig');
//获取model所对应的数据库名
if($this->modelConfig)foreach($this->modelConfig as $key=>$val){
if(in_array($modelName,$val)){
$dbName = $key;
break;
}
}
return $dbName;
}
/**
* 切换数据库连接
* @param unknown_type $dbtype
*/
protected function changeConn($dbtype = 'read'){
if($this->dbType == $dbtype && self::$dataBase[$this->dbName] !== null)
return self::$dataBase[$this->dbName];
$this->dbName = $this->getDbName();
if(Yii::app()->getComponent($this->dbName.'_'.$dbtype) !== null){
self::$dataBase[$this->dbName] = Yii::app()->getComponent($this->dbName.'_'.$dbtype);
return self::$dataBase[$this->dbName];
}
$this->dbConfig = $this->getConfig('dbConfig',$this->dbName);
//跟据类型取对应的配置(从库是随机值)
if($dbtype == 'write'){
$config = $this->dbConfig[$dbtype];
}else{
$slavekey = array_rand($this->dbConfig[$dbtype]);
$config = $this->dbConfig[$dbtype][$slavekey];
}
//将数据库配置加到component中
if($dbComponent = Yii::createComponent($config)){
Yii::app()->setComponent($this->dbName.'_'.$dbtype,$dbComponent);
self::$dataBase[$this->dbName] = Yii::app()->getComponent($this->dbName.'_'.$dbtype);
$this->dbType = $dbtype;
return self::$dataBase[$this->dbName];
} else
throw new CDbException(Yii::t('yii','Model requires a "changeConn" CDbConnection application component.'));
}
/**
* 保存数据前选择 主 数据库
*/
protected function beforeSave(){
parent::beforeSave();
$this->changeConn('write');
return true;
}
/**
* 删除数据前选择 主 数据库
*/
protected function beforeDelete(){
parent::beforeDelete();
$this->changeConn('write');
return true;
}
/**
* 读取数据选择 从 数据库
*/
protected function beforeFind(){
parent::beforeFind();
$this->changeConn('read');
return true;
}
/**
* 获取master库对象
*/
public function dbWrite(){
return $this->changeConn('write');
}
/**
* 获取slave库对象
*/
public function dbRead(){
return $this->changeConn('read');
}
}