php - 未抛出 PDO 异常

Question

我是 PDO 的新手，关于它的一些事情让我感到困惑，我尝试创建一个测试函数来查看是否会为无效查询抛出异常，但没有抛出任何东西。

这是代码

<?php
include_once("/var/www/include/constants.php");

class DB{
    private $DBH; 

    public function DB(){
        try{
            $DBH = new PDO("mysql:host=".DB_SERVER.";dbname=".DB_NAME, DB_USER, DB_PASS);   
        }
        catch(PDOException $e) {  
            echo $e->getMessage(); 
        }
    }

    public function test(){
        try{
            $DBH->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );  
            $DBH->prepare('DELECT id FROM users');  
        }
        catch(PDOException $e) {  
            echo $e->getMessage();  

        }
    }

};

/* Create database connection */
$db = new DB;
$db->test();

?>

Answer 1

除了缺少对数据库句柄的 $this 的引用外，您还需要告诉 PDO 它不能模拟准备。下面的代码将抛出这样的异常:

SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DELECT id FROM users' at line 1

class DB{
    private $DBH; 

    public function DB(){
        try{
            $this->DBH = new PDO("mysql:host=localhost;dbname=movies", 'root', 'jsat12');   
            $this->DBH->setAttribute(PDO::ATTR_EMULATE_PREPARES, false );
      }
        catch(PDOException $e) {  
            echo $e->getMessage(); 
        }
    }

    public function test(){
        try{
            $this->DBH->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );  
            $this->DBH->prepare('DELECT id FROM users');  
        }
        catch(PDOException $e) {  
            echo $e->getMessage();  

        }
    }

};

/* Create database connection */
$db = new DB;
$db->test();