host  = 'localhost';        $this->user = 'xuwm';        $this->pwd = 'bW7LA2pMDAEtnVB7';        $this->dbName = 'gamejj';        $this->charset='utf8';        //连接        $this->connect($this->host, $this->user, $this->pwd);        //选库        $this->switchDb($this->dbName);        //设置字符集        $this->setChar($this->charset);    }    //负责连接    private function connect($host, $user, $pwd){
              $conn = mysql_connect($host, $user, $pwd);         if (!$conn) {
                  echo "Unable to connect to DB: " . mysql_error();            exit;        }        $this->conn = $conn;    }    //选库    public function switchDb($db){
              $sql = 'use ' . $db; //注意user 和 ' 有一个空格        $this->query($sql);    }    //设置字符集    public function setChar($char){
              $sql = 'set names ' . $char;        $this->query($sql);    }    //关闭连接    public function close(){
              mysql_close($this->conn);    }    //负责发送sql查询    public  function query($sql){
              $result = mysql_query($sql, $this->conn);        return $result;    }    //获取多行多列的select结果    public function getAll($sql){
              $list  = array();        $result = $this->query($sql);        if(!$result)            return false;        while($row= mysql_fetch_assoc($result)){
                  $list[] = $row;        }        return $list;    }    //获取一行数据 常用于 聚合函数    public function getRow($sql){
              $result = $this->query($sql);        if(!$result)            return false;        $row= mysql_fetch_assoc($result);        return $row;    }     //获取一个值    public function getOne($sql){
              $result = $this->query($sql);        if(!$result)            return false;        $row= mysql_fetch_row($result);        return $row[0];    }}//$mysql = new SqlHelper();/*var_dump($mysql);$sql = "insert goods values(1121, 4, '苹果')";$mysql->query($sql);$sql = 'select * from goods';$list = $mysql->getAll($sql);var_dump($list);$sql = 'select * from goods where goods_id=4';$list = $mysql->getRow($sql);var_dump($list);$sql = 'select count(*) from goods';$list = $mysql->getOne($sql);var_dump($list);*/