一个PDO类

下面是在网上借鉴的一个PDO类：

<?php
class Database{
    private $host = DB_HOST;
    private $user = DB_USER;
    private $pass = DB_PASS;
    private $dbname = DB_NAME;

    private $dbh;
    private $error;

    private $stmt;

        /*
        function __construct 
        */
    public function __construct(){
        // set DSN
        $dsn = 'mysql:host='.$this->host.';dbname='.$this->dbname;
        //set options
        $options = array(
            PDO::ATTR_PERSISTENT => true,
            PDO::ATTR_ERRMODE    => PDO::ERRMODE_EXCEPTION    
        );
        //create a new PDO instanace
        try{
            $this->dbh = new PDO($dsn,$this->user,$this->pass,$options);
        }
        //catch any errors
        catch(PDOException $e){
            $this->error = $e->getMessage();
        }
    }

        /*
        function query
        */
    public function query($query){
        $this->stmt = $this->dbh->prepare($query);
    }    

        /*
          fucntion bindValue
        */
    public function bind($param,$value,$type){
        if (is_null($type)) {
        switch (true) {
            case is_int($value):
                $type = PDO::PARAM_INT;
                break;
            case is_bool($value):
                $type = PDO::PARAM_BOOL;
                break;
            case is_null($value):
                $type = PDO::PARAM_NULL;
                break;
            default:
                $type = PDO::PARAM_STR;
        }
    }
    $this->stmt->bindValue($param, $value, $type);
    }    

    /*
      functin execute
    */  
    public function execute(){
        return $this->stmt->execute();
    }
    /*
    获得结果集  关联数组
    */
    public function resultset(){
    $this->execute();
    return $this->stmt->fetchAll(PDO::FETCH_ASSOC);
    }


    /* 获得单条数据*/
    public function single(){
        $this->execute();
        return $this->stmt->fetch(PDO::FETCH_ASSOC);
    }
    
    public function rowCount(){
            return $this->stmt->rowCount();
    }

    public function lastInsertId(){
        return $this->dbh->lastInsertId();
    }

    public function beginTransaction(){
        return $this->dbh->beginTransaction();
    }

    public function endTransaction(){
        return $this->dbh->commit();
    }

    public function cancelTransaction(){
           return $this->dbh->rollBack();
    }

    public function debugDumpParams(){
        return $this->stmt->debugDumpParams();
    }

}
?>

这个类的具体使用：

 try{
      $database = new Database();
      $database->beginTransaction();
      $tm_startt = strtotime($_POST['time_start']);
      $tm_end = strtotime($_POST['time_end']);
      $database->query('insert into gua_user(user_name, user_nicheng, user_type, user_comment,user_created,user_end) values (:user_name, :user_nicheng, :user_type, :user_comment,:user_created,:user_end)');
      $database->bind(':user_name', $_POST['username']);
      $database->bind(':user_nicheng', $_POST['user_nick']);
      $database->bind(':user_type', $_POST['user_type']);
      $database->bind(':user_comment', $_POST['comment']);
      $database->bind(':user_created', $tm_startt);
      $database->bind(':user_end', $tm_end);
      $database->execute();
      //获得影响的行数
      $rows = $database->rowCount();
      //获得本条数据的id
      $id = $database->lastInsertId();
      if($rows<1){
          throw new PDOexception('第一句sql语句执行失败！', '01');
      }
      //产生随机字符串 salt
      $salt = $database->salt();
      $password = md5($_POST['password'].$salt);
      $database->query('insert into gua_salt(uid,salt,password) values (:uid,:salt,:password)');
      $database->bind(':uid',$id);
      $database->bind(':salt',$salt);
      $database->bind(':password',$password);
      $database->execute();
      $rows = $database->rowCount();
      if($rows<1){
          throw new PDOexception('第二句sql语句执行失败！', '02');
      }
      $database->endTransaction();
      }catch(PDOexception $e){
          //如果有异常被抛出 则事务失败 执行事务回滚
          $database->cancelTransaction();
          //输出异常信息
          echo $e->getCode().'-----'.$e->getMessage();
      }

使用事物，注意表的类型要是innodb的。

参考网站：http://culttt.com/2012/10/01/roll-your-own-pdo-php-class/