php - PDO 错误代码始终为 00000，即使出现错误

Question

我正在运行 PHP 7.2.16

不确定何时启动，PDO errorCode() 或 errorInfo()[0] 现在总是显示 00000，即使有错误也是如此

$pdo = new \PDO('mysql:host=localhost;dbname=mydb', 'root', 'pwd');
$sth = $pdo->prepare('select now() and this is a bad SQL where a - b from c');
$sth->execute();
$row = $sth->fetchAll();
$err = $sth->errorInfo();
echo $sth->errorCode();
print_r($row);
print_r($err);

结果如下:

00000Array
(
)
Array
(
    [0] => 00000
    [1] => 1064
    [2] => You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a bad SQL where a - b from c' at line 1
)

但是，我刚刚做了一个新的测试，通过删除 $sth->fetchAll() 或者在这一行之前得到错误，它正确显示:

Array
(
    [0] => 42000
    [1] => 1064
    [2] => You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a bad SQL where a - b from c' at line 1
)

好的 - 解决方案是:

get the error code immediately after execute() and before any fetch

Answer 1

我用 PHP 7.1.23 测试了这段代码:

$pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, true);
$sth = $pdo->prepare('select now() and this is a bad SQL where a - b from c');
if ($sth === false) {
  echo "error on prepare()\n";
  print_r($pdo->errorInfo());
}
if ($sth->execute() === false) {
  echo "error on execute()\n";
  print_r($sth->errorInfo());
}

输出:

error on execute()
Array
(
    [0] => 42000
    [1] => 1064
    [2] => 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 'a bad SQL where a - b from c' at line 1
)

然后我测试了相同的代码，除了在禁用模拟准备之后:

$pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);

输出:

error on prepare()
Array
(
    [0] => 42000
    [1] => 1064
    [2] => 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 'a bad SQL where a - b from c' at line 1
)

Fatal error: Uncaught Error: Call to a member function execute() on boolean

故事的寓意:

• 当使用模拟的准备好的语句时，prepare() 是空操作，错误会延迟到 execute()。我建议禁用模拟准备，除非您使用的数据库不支持准备语句(我不知道任何 RDBMS 产品的当前版本不能执行真正的准备语句)。

• 检查 prepare() 的错误时，使用 $pdo->errorInfo()。

• 检查 execute() 的错误时，使用 $stmt->errorInfo()。