我收到此错误代码:为 foreach() 提供的参数无效 [英] I'm getting this error code: Invalid argument supplied for foreach()
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问题描述
我正在学习 PDO 并且感到非常困惑,我在下面有这段代码,对我来说一切正常,但是我收到了这个错误代码,我不知道该怎么做才能修复它,请帮助我:
I am learning PDO and i am getting very confused, I have this piece of code below and all looks right to me however I'm getting this error code and I don't know what I have to do to fix it, please help me:
<?php
$hostname='localhost';
$username='root';
$password='';
try {
$dbh = new PDO("mysql:host=$hostname;dbname=stickercollections",$username,$password);
echo 'Connected to Database<br/>';
$sql = "SELECT * FROM stickercollections";
foreach ($dbh->query($sql) as $row)
{
echo $row["collection_brand"] ." - ". $row["collection_year"] ."<br/>";
}
$dbh = null;
}
catch(PDOException $e)
{
echo $e->getMessage();
}
?>
错误代码
Invalid argument supplied for foreach() in /Applications/XAMPP/xamppfiles/htdocs/GOTSWAPMAIN/index.php on line 11
推荐答案
尝试增加错误模式:
<?php
$hostname='localhost';
$username='root';
$password='';
try {
$dbh = new PDO("mysql:host=$hostname;dbname=stickercollections",$username,$password);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); // <== add this line
echo 'Connected to Database<br/>';
$sql = "SELECT * FROM stickercollections";
foreach ($dbh->query($sql) as $row)
{
echo $row["collection_brand"] ." - ". $row["collection_year"] ."<br/>";
}
$dbh = null;
}
catch(PDOException $e)
{
echo $e->getMessage();
}
?>
pdo.error-handling 说,你也可以使用
pdo.error-handling says, you can alternatively use pdo.errorcode and pdostatement.errorcode (or like) to get more info, but I think throw exception is better way to handle bad connections, not resolved hosts etc.
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