pdo删除不起作用

Question

<?php
$db = new PDO('mysql:host=localhost;dbname=wordpress', 'root','');
//---------prepare
$delete3 = $db->prepare("DELETE FROM wp_term_relationships WHERE object_id=:id");
$delete2 = $db->prepare("DELETE FROM wp_posts WHERE ID=:id");
$delete = $db->prepare("DELETE FROM wp_postmeta WHERE post_id=:id");;
$select = $db->prepare("SELECT post_id FROM reference WHERE x_id=?");
$delete->bindParam(':id', $id, PDO::PARAM_STR);
$delete2->bindParam(':id', $id, PDO::PARAM_STR);
$delete3->bindParam(':id', $id, PDO::PARAM_STR);
//----------
echo 'conected-----';
{$delfeed = 'LOTS OF NUMBERS';}
$array = explode(',',$delfeed);
foreach($array as $deadman){
   $select->execute(array($deadman));
   $row = $select->Fetch(PDO::FETCH_ASSOC);
   $id = $row['post_id'];
      if ($id){
        echo "$id"."\n";
        $delete->execute();
        $delete2->execute();
        $delete3->execute();
}}
echo 'done!';
?>

它是一个简单的删除脚本，但不会删除， 它确实会打印正确的$ id的女巫，直到在那里工作，但删除会变成香蕉，再次检查表名，列...尝试与问号占位符一起使用bind参数，但是什么也没做更新：它卡在foreach中数组的第一项上

Answer 1

问题是您要在创建$id变量之前对其进行设置。

<?php
$db = new PDO('mysql:host=localhost;dbname=wordpress', 'root','');

$delete3 = $db->prepare("DELETE FROM wp_term_relationships WHERE object_id=?");
$delete2 = $db->prepare("DELETE FROM wp_posts WHERE ID=?");
$delete = $db->prepare("DELETE FROM wp_postmeta WHERE post_id=?");
$select = $db->prepare("SELECT post_id FROM reference WHERE x_id=?");

foreach($array as $deadman){
   $select->execute(array($deadman));
   $row = $select->Fetch(PDO::FETCH_ASSOC);
   $id = $row['post_id'];
   if ($id) {
      echo "$id"."\n";
      $data = array($id);
      $delete->execute($data);
      $delete2->execute($data);
      $delete3->execute($data);
   }
   $id++;
}
echo 'done!';
?>

我确实更新了您的代码，因为有些地方没有意义，例如$delfeed是一个空字符串，即使覆盖了$id变量也增加了$id变量，并放置了随机大括号。 但是正如您所看到的，在if($id)检查中，我将变量绑定在那里。

除了使用我的方法，您还可以在文档顶部将变量$id指定为0值； 然后，在完成所有prepare语句之后，可以使用功能bindParam代替bindValue 。

$id = 0;

// Prepare Statements

$delete->bindParam(':id', $id, PDO::PARAM_STR);
$delete2->bindParam(':id', $id, PDO::PARAM_STR);
$delete3->bindParam(':id', $id, PDO::PARAM_STR);

// Rest of Original Code With No Changes

之所以起作用，是因为bindParam在查询执行时通过引用传递。 参见PHP bindParam文档以及此答案。

编辑：解决方案2解决Foreach问题

<?php
$db = new PDO('mysql:host=localhost;dbname=wordpress', 'root','');

$delete3 = $db->prepare("DELETE FROM wp_term_relationships WHERE object_id=:id");
$delete2 = $db->prepare("DELETE FROM wp_posts WHERE ID=:id");

// Had a double semicolon trailing the function. Removed one of them
$delete = $db->prepare("DELETE FROM wp_postmeta WHERE post_id=:id");
$select = $db->prepare("SELECT post_id FROM reference WHERE x_id=?");

$id = 0; // Define Variable BEFORE bindParam

$delete->bindParam(':id', $id, PDO::PARAM_STR);
$delete2->bindParam(':id', $id, PDO::PARAM_STR);
$delete3->bindParam(':id', $id, PDO::PARAM_STR);


$delfeed = ''; // Why Have Curly Braces around this?

$array = explode(',',$delfeed);

foreach($array as $deadman) {
   $select->execute(array($deadman));
   $row = $select->Fetch(PDO::FETCH_ASSOC);
   $id = $row['post_id'];
   if ($id){
      echo "$id"."\n";
      $delete->execute();
      $delete2->execute();
      $delete3->execute();
   }
}
echo 'done!';
?>