/**

* Mysql代理类 支持Master/Slave 读写分离 客户端不需担心连Master/Slave 本类自动代理完成

*

* @author 小黑米

* @package Core.DB

* @version 1.0 beat

* @copyright 2008-5-8

* @todo 下一步准备开发支持多memcache的代理

*/

/*

配置:

$dns = array(

array(//第一个为主库

"host"=>"localhost",

"user"=>"root",

"pwd"=>"123456",

"port"=>3306,

"db"=>"phpexp",

),

//剩下的都是从库

array(

"host"=>"localhost",

"user"=>"root",

"pwd"=>"123456",

"port"=>3306,

"db"=>"phpexp",

),

);

执行方法:

Mysql::getInstance()->fetchResult("select * from frame_role");

Mysql::getInstance()->query("update frame_role set name=test limit 1");

SQL记录追踪:

array(2) {

["times"] => int(2)

["sqls"] => array(2) {

[0] => array(2) {

["sql"] => string(24) "select * from frame_role"

["type"] => string(5) "slave"

}

[1] => array(2) {

["sql"] => string(39) "update frame_role set name=test limit 1"

["type"] => string(6) "master"

}

}

}

执行结果:

array(2) {

[0] => array(4) {

["id"] => string(1) "1"

["rname"] => string(7) "tourisa"

["rmark"] => string(6) "游客"

["rprev"] => string(6) "a:0:{}"

}

[1] => array(4) {

["id"] => string(1) "2"

["rname"] => string(7) "tourise"

["rmark"] => string(7) "游客1"

["rprev"] => string(6) "a:0:{}"

}

}

*/

class Mysql{

/**

* 单例模式

*

* @var resource

*/

private static $instance = null;

/**

* Master 单例

*

* @var resource

*/

private static $master = null;

/**

* Slave 单例

*

* @var resource

*/

private static $slave = null;

/**

* 数据库执行记录

*

* @var array

*/

public static $querys = array("times"=>0,"sqls"=>array());

private $_tmpRes = null;

/**

* 获取单例

*

* @return resource

*/

public static function getInstance(){

if(!self::$instance)

{

self::$instance = new Mysql();

}

return self::$instance;

}

/**

* 构造函数 保留

*

*/

private function __construct(){}

/**

* 取记录 并根据自动hash结果集

*

* @param string $sql

* @param string $hashBy

* @return array

*/

public function fetchResult($sql,$hashBy=null){

$return = array();

$this->query($sql);

if(!$this->_tmpRes) httpError("handler500","SQL:{$sql} 执行失败");

if(!$hashBy)

{

while ($res = mysql_fetch_assoc($this->_tmpRes))

{

$return[] = $res;

}

}

else

{

while ($res = mysql_fetch_assoc($this->_tmpRes))

{

$return[$res[$hashBy]] = $res;

}

}

return $return;

}

/**

* 执行指令

*

* @param string $sql

* @return resource

*/

public function query($sql){

self::$querys['times']++;

$conn = $this->_checkSql($sql);

self::$querys['sqls'][] = array("sql"=>$sql,"type"=>$conn['type']);

// d(mysql_query($sql,$this->conn) or die(mysql_error()),false);

$this->_tmpRes = mysql_query($sql,$conn['conn']) or httpError("handler500",mysql_error());

}

/**

* 分析SQL语句，自动分配到主库，从库

*

* @param string $sql

* @return resource

*/

private function _checkSql($sql){

global $dns;

$_n = count($dns);

if(count($dns)===1)

{//主从一样

return $this->_getHelper($dns[0],"master");

}

else

{

$type = substr($sql,0,strpos($sql," "));

if ($type === 'select')

{//读从库

if($_n=2)

{

$ddns = $dns[1];

}

else

{//随即取一个从库

$ddns = $dns[mt_rand(1,$_n-1)];

}

return $this->_getHelper($ddns);

}

else

{//更新主库

return $this->_getHelper($dns[0],"master");

}

}

}

/**

* 主从库助手函数

*

* @param array $dns

* @param string $type Slave/Master

* @return resource

*/

private function _getHelper($dns,$type="slave"){

if(!self::$$type)

{

self::$$type = new Helper($dns);

}

return array("conn"=>self::$$type->getConn(),"type"=>$type);

}

/**

* 影响记录数

*

* @param string $sql

* @return array

*/

public function getAffectRows(){

return mysql_affected_rows();

}

/**

* 最后插入的ID

*

* @param string $sql

* @return array

*/

public function getLastInsertId(){

return mysql_insert_id();

}

}

class Helper{

private $conn = null;

public function __construct(&$dns){

$this->conn = mysql_connect($dns['host'].":".$dns['port'],$dns['user'],$dns['pwd']) or httpError("handler500","数据库出错");

mysql_select_db($dns['db'],$this->conn) or httpError("handler500",$dns['db']."库出现异常");

}

public function getConn(){

return $this->conn;

}

}

?>