确保PDO获取方法的结果为“假".是错误或空结果 [英] ensure that PDO fetch method result "false" is a error or empty result

问题描述

如何识别php PDO mysql驱动程序的执行错误导致的读取错误或空结果?

How can I recognize a fetch error or empty result from a execute error with php PDO mysql driver?

  $sql = ' SELECT * ';
  $sql .= ' FROM test ';
  $sql .= ' WHERE id = 432 ';

  $statement = $this->_db->prepare($sql);
  $status = $statement->execute();

  var_dump($status);

  $result = $statement->fetch(\PDO::FETCH_ASSOC);

  var_dump($result);

  output:
  bool(true)
  bool(false)

因此，我准备了pdo语句，然后执行sql，并且由于没有错误，所以状态为true.然后，我获取结果，在这种特定情况下，id = 432的行不存在.因此fetch方法返回false.我的问题是，当发生错误时，fetch方法也会返回false！

So, I prepare statement with pdo, then execute sql, and status is true because there aren't error. Then I fetch result, and in this specific case a row with id = 432 isn't exist. So fetch method return false. My problem is that fetch method return false also when there is a error!.

如何确定获取假"结果是错误还是空结果?

How can I sure that fetch "false" result is a error or empty result?

推荐答案

如果出现错误，则PDO会引发一个异常，您可以捕获该异常.用try catch包装您的代码，并且应该捕获所有异常.

If there's an error then PDO will throw an exception which you can catch. Wrap your code with a try catch and that should catch any exceptions.

try {
    $rs = $db->prepare('SELECT * FROM foo');
    $rs->execute();
    $foo = $rs->fetchAll();
} catch (Exception $e) {
    echo 'Error: '.$e->getMessage();
}

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