mysql 單例模式

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require_once ('mysql_config.php');class msyql_db{   static private $_instance;  private $com;  private function __construct($db_host,$name,$db_name,$db_pwd){   //外部不能直接執行個體化   $this->com=mysql_connect($db_host,$name,$db_pwd) or die("連結資料庫失敗");   mysql_select_db($db_name);   mysql_query("set names utf8");  }  private function __clone(){}   //外部不能複製類  static public function instance_com($dbhost,$name,$dbname,$sbpwd){   if(!isset(self::$_instance)){    //self表示類本身  調用靜態屬性時要使用 ：：    self::$_instance= new self($dbhost,$name,$dbname,$sbpwd);  //執行個體化自己    return self::$_instance;   }else{     return self::$_instance;   }  }  function select($sql){ //獲得多條資料，二維數組   $result=mysql_query($sql);    $arr=array();    while($row=mysql_fetch_assoc($result)){    $arr[]=$row;    }    return $arr;  }    function select1($sql){  $result=mysql_query($sql);  return mysql_fetch_assoc($result);  }    function count($sql){  $result=mysql_query($sql);  return mysql_num_rows($result);  }    function query($sql){  return mysql_query($sql);  }    function get_last_id(){  $sql="select last_insert_id() as last_id";  $result=mysql_query($sql);  $result=mysql_fetch_assoc($result);  return $result["last_id"];  }    function insert($post){  //insert 語句 合并欄位和對應的值  $cloum="";$value="";foreach ($post as $k=>$v){if ($k!="type"){$cloum .= ",`".$k."`";$value .= ",'".$v."'";}}$cloum=substr($cloum,1);$value=substr($value,1);return array("cloum"=>$cloum,"value"=>$value);  }    function update($post){ //update 語句 合并欄位和對應的值  $str="";  foreach ($post as $k=>$v){  if ($k!="type"){  $str .= ",`".$k."`='".$v."'";  }  }  return substr($str,1);  }   } //$test=new one("localhost","root","online",""); $db = msyql_db::instance_com($db_host,$db_user,$db_db,$db_pwd);  //調用靜態方法的時候要使用：：

mysql 單例模式