问题描述
最近，我鼓励使用PHP代码中的怪异错误.就像将PDOStatement对象与foreach(){}一起使用时，会忽略内部的try{}catch(){}块.这是触发此行为的测试代码:
Recently I've encouraged weird error in PHP code. It's like the inner try{}catch(){} block is omited when using PDOStatement object with foreach(){}. Here is my test code which triggers this behaviour:
<?php
/*
// THIS WORKS AS EXPECTED, JUST UNCOMMENT
try{
for($i = 0; $i < 3; $i++){
try{
echo "\nTHROWING EXCEPTION\n\n";
throw new Exception("AAAAAAAAAAAAAAAAAAAAAAAAA");
echo "EXCETION THROWN (SHOULD NOT SHOW)\n";
}catch(Exception $err){
echo "========= INNER CATCH =========\n";
echo $err->getMessage() . "\n";
}
}
}catch(Exception $e){
echo "=========== OUTER CATCH ===========\n";
die($e->getMessage() . "\n");
}
die("\nEVERYTHING OK\n");
*/
$dsn = "mysql:dbname=test_pdo;host=localhost";
try {
$dbh = new PDO($dsn, 'root', "", array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));
$dbh->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$dbh->exec("
CREATE TABLE IF NOT EXISTS `test` (
`id` int(10) unsigned NOT NULL,
`name` varchar(255) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
");
$dbh->exec("TRUNCATE test");
$dbh->exec("
INSERT INTO test (id, name) VALUES
(1, 'JOHN DOE 1'), (2, 'JOHN DOE 2'),
(3, 'JOHN DOE 3'), (4, 'JOHN DOE 4')
");
echo "\nRECORDS CREATED\n";
$sth = $dbh->prepare("SELECT id FROM test WHERE id = ?");
foreach(array(2, 3, 4) as $id){
$sth->execute(array($id));
$i = 0;
foreach($sth as $row){
$num = $row['id'] - 1;
// this sql should throw 2300 error duplicate key
$sql = "UPDATE test SET name = 'JOHN DOE $num' WHERE id = {$row['id']}";
try{
echo "\nSENDING QUERY: $sql\n\n";
$dbh->exec($sql);
}catch(Exception $err){
$code = $err->getCode();
$msg = $err->getMessage();
//duplicate key error?
if($err->getCode() != "23000"){
echo "THROWING EXCEPTION FROM INNER CATCH.\n ERROR CODE: $code\n";
throw $err;
}
echo <<<TXT
============ GOOD CATCH ============
ERROR CODE: $code
ERROR MSG: $msg
SQL: $sql
TXT;
}
}
}
}catch(Exception $e){
$code = $e->getCode();
$msg = $e->getMessage();
echo <<<TXT
============ WRONG CATCH ===========
ERROR CODE: $code
ERROR MSG: $msg
TXT;
}
这在我的本地主机(带有Suhosin-Patch(cli)的PHP 5.3.6-13ubuntu3.6)和服务器(PHP 5.2.17)上输出如下内容:
This outputs something like this on my localhost (PHP 5.3.6-13ubuntu3.6 with Suhosin-Patch (cli)) and on server (PHP 5.2.17):
RECORDS CREATED
SENDING QUERY: UPDATE test SET name = 'JOHN DOE 1' WHERE id = 2
============ GOOD CATCH ============
ERROR CODE: 23000
ERROR MSG: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'JOHN DOE 1' for key 'name'
SQL: UPDATE test SET name = 'JOHN DOE 1' WHERE id = 2
============ WRONG CATCH ===========
ERROR CODE: 23000
ERROR MSG: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'JOHN DOE 1' for key 'name'
不知道为什么，但是当我将foreach($sth as $row){更改为foreach($sth->fetchAll() as $row){时，一切都按预期进行:
Don't know why but when I change foreach($sth as $row){ to foreach($sth->fetchAll() as $row){ everythings works as expected:
RECORDS CREATED
SENDING QUERY: UPDATE test SET name = 'JOHN DOE 1' WHERE id = 2
============ GOOD CATCH ============
ERROR CODE: 23000
ERROR MSG: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'JOHN DOE 1' for key 'name'
SQL: UPDATE test SET name = 'JOHN DOE 1' WHERE id = 2
SENDING QUERY: UPDATE test SET name = 'JOHN DOE 2' WHERE id = 3
============ GOOD CATCH ============
ERROR CODE: 23000
ERROR MSG: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'JOHN DOE 2' for key 'name'
SQL: UPDATE test SET name = 'JOHN DOE 2' WHERE id = 3
SENDING QUERY: UPDATE test SET name = 'JOHN DOE 3' WHERE id = 4
============ GOOD CATCH ============
ERROR CODE: 23000
ERROR MSG: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'JOHN DOE 3' for key 'name'
SQL: UPDATE test SET name = 'JOHN DOE 3' WHERE id = 4
我是否发现了错误或我做错了什么?有人可以确认这种行为吗?谢谢
Did I found a bug or am I doing something wrong? Can someone confirm that behaviour? Thx
//编辑
将PHP版本升级到5.3.10似乎可以解决此问题.寻求帮助...
Upgrading PHP version to 5.3.10 seems to fix this issue. Thx for help...
推荐答案
不，您不能直接从PDO返回的结果进行迭代.这不是PDO例外，当您尝试执行此操作时，它是PHP，它不是具有迭代器的数组或对象.
No, the result sent back from PDO is not something you can directly iterate over. It's not a PDO exception, it's a PHP when you try to do that--it's not an array or an object that has an iterator.
获取时会创建一个在foreach循环中有效的数组.
When you fetch it creates an array that is valid in the foreach loop.
这篇关于尝试catch块不适用于pdo语句和foreach的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！