php实现的支持读写分离的MySQL类

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Freigeben： 2016-07-25 08:56:07

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/**
* MySQL读写分离类
* $db_config = array(
* 'master' => array('host'=>'localhost:3306','user'=>'admin','passwd'=>'123456','db'=>'stat'),
* 'slave' => array(
* array('host'=>'localhost:3307','user'=>'admin','passwd'=>'123456','db'=>'stat'),
* array('host'=>'localhost:3308','user'=>'admin','passwd'=>'123456','db'=>'stat')
* )
* );
*
* 注释：如果slave有多个时随机连接其中的一个
* 最后编辑：bbs.it-home.org
*/
/*
$db_config = array(
'master' => array('host'=>'localhost:3306','user'=>'admin','passwd'=>'123456','db'=>'stat'),
'slave' => array(
array('host'=>'localhost:3307','user'=>'admin','passwd'=>'123456','db'=>'stat'),
array('host'=>'localhost:3308','user'=>'admin','passwd'=>'123456','db'=>'stat')
)
);
$db = MySQL::getInstance('','r-w');
$sql = "select * from admin";
$rs = $db->query($sql);
while ($row = $db->fetch($rs)){
echo "uid:".$row['uid']." ".$row['userName']."
";
}
echo "

";
*/
class MySQL
{
private static $_instance = null;//数据库连接实例
private static $_master = null;//主数据库连接实例
private static $_slave = null;//重数据库连接实例
public $_config = array();//数据库连接配置信息
public $_res = null;//查询实例句柄
public $_flag = '';//标识当前语句是在主还是重数据库上执行
public $_link = null;
/**
* 单实例
* Enter description here ...
* @param unknown_type $dbname
* @param unknown_type $mode
*/
public static function & getInstance($dbname='',$mode='rw'){
if (is_null(self::$_instance)){
self::$_instance = new self();
self::$_instance->__getConf();
self::$_instance->connect($dbname,$mode);
}
return self::$_instance;
}
/**
* 获取数据库配置信息
* Enter description here ...
*/
public function __getConf(){
global $db_config;
$this->_config['master'] = $db_config['master'];
$this->_config['slave'] = $db_config['slave'];
}
/**
* 数据库连接
* Enter description here ...
* @param $dbname 指定连接的数据库名，默认情况下连接配置文件的库
* @param $mode rw表示连接主库，r-w表示读写分离
*/
public function connect($dbname='',$mode = 'rw'){
if($mode == 'rw'){
if(is_null(self::$_master)){
$this->_master = $this->_slave = $this->conn_master($dbname);
}
}else{
if(is_null(self::$_master)){
$this->_master = $this->conn_master($dbname);
}
if(is_null(self::$_slave)){
$this->_slave = $this->conn_slave($dbname);
}
}
}
/**
* 连接到主数据库服务器
* Enter description here ...
*/
public function conn_master($dbname=''){
$_link = mysql_connect($this->_config['master']['host'],$this->_config['master']['user'],$this->_config['master']['passwd'],true) or die ("Connect ".$this->_config['master']['host']." fail.");
mysql_select_db(empty($dbname)?$this->_config['master']['db']:$dbname,$_link) or die(" The DB name ".$this->_config['master']['db']." is not exists.");
mysql_query("set names utf8",$_link);
return $_link;
}
/**
* 连接到从数据库服务器
* Enter description here ...
*/
public function conn_slave($dbname=''){
$offset = rand(0,count($this->_config['slave'])-1);
$_link = @mysql_connect($this->_config['slave'][$offset]['host'],$this->_config['slave'][$offset]['user'],$this->_config['slave'][$offset]['passwd'],true) or die(" Connect ".$this->_config['slave'][$offset]['host']." fail.");
mysql_select_db(empty($dbname)?$this->_config['slave'][$offset]['db']:$dbname,$_link) or die(" The DB name ".$this->_config['slave'][$offset]['db']." is not exists.");
mysql_query("set names utf8",$_link);
return $_link;
}
/**
* 执行数据库查询
* Enter description here ...
* @param string $sql
*/
public function query($sql,$master=true){
if($master == true || (substr(strtolower($sql),0,6) != 'select') && $master == false){
$this->_res = mysql_query($sql,$this->_master);
if(!$this->_res){
$this->_error[] = mysql_error($this->_master);
}
$this->_flag = 'master';
$this->_link = $this->_master;
} else {
$this->_res = mysql_query($sql,$this->_slave);
if(!$this->_res){
$this->_error[] = mysql_error($this->_slave);
}
$this->_flag = 'slave';
$this->_link = $this->_slave;
}
return $this->_res;
}
/**
* 获取单行记录
* Enter description here ...
* @param mixed $rs
*/
public function get($rs=''){
if(empty($rs)){
$rs = $this->_res;
}
return mysql_fetch_row($rs);
}
/**
* 获取多行记录
* Enter description here ...
* @param mixed $rs
* @param $result_type
*/
public function fetch($rs = ''){
if(empty($rs)){
$rs = $this->_res;
}
return mysql_fetch_array($rs,MYSQL_ASSOC);
}
/**
* 插入数据
* Enter description here ...
* @param unknown_type $sql
*/
public function add($sql){
$rs = $this->query($sql);
if($rs)
return mysql_insert_id($this->_link);
return false;
}
/**
* 更新数据
* Enter description here ...
* @param unknown_type $sql
*/
public function update($sql){
if(empty($sql)) return false;
$rs = $this->query($sql);
if($rs)
return $this->fetchNum();
return false;
}
/**
* 获取上一条语句影响的行数
* Enter description here ...
*/
public function fetchNum(){
return mysql_affected_rows($this->_link);
}
/**
* 析构函数,释放数据库连接资源
* Enter description here ...
*/
public function __destruct(){
mysql_close($this->_link);
}
}

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