PDO 更新会创建新记录，而不是更新记录 - PDO UPDATE creates a new record instead of updating one

PDO UPDATE creates a new record instead of updating one

本文关键字：更新新记录创建 PDO | 更新日期: 2023-09-27

我使用以下代码来更新记录。不好的是它没有更新记录，而是添加了新记录。

我做错了什么？我希望它更新记录而不是创建现在的记录。

我的修改网址如下所示：http://randomsite.com/modify.php?id=1

修改.php代码：

<?php
    require_once("connect.php");
    $query = "SELECT * FROM cars WHERE id = :id";
    $result = $odb->prepare($query);
    $result->execute(array(':id' => $_REQUEST['id']) );
    while  ($row = $result->fetch(PDO::FETCH_ASSOC)) { ?>

    <h1>Modify a car</h1>
    <form  action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
    Brand:      <input type="text" name="brand" value="<?php echo $row['brand']; ?>"  /><br />
    Model:      <input type="text" name="model" value="<?php echo $row['model']; ?>"  /><br />
    Year:       <input type="text" name="year"  value="<?php echo $row['year'];  ?>"   /><br />
    ID:     <input type="text" name="id"  value="<?php echo $row['id'];  }?>"   /><br />
    <input type="submit" value="Modify" />
    </form>
    <?php
    if(isset($_POST['submit'])) {
    $id    = $_POST['id'];
    $brand = $_POST['brand'];
    $model = $_POST['model'];
    $year  = $_POST['year'];
    $q     = "UPDATE cars WHERE id = $_GET[id] (id, brand, model, year) VALUES(:id, :brand, :model, :year)";
    $query = $odb->prepare($q);
    $results = $query->execute(array(
            ":id"    => $id,
            ":brand" => $brand,
            ":model" => $model,
            ":year"  => $year,
    )); 
}
?>

你的 SQL 应该看起来更像这样：

   $q = "UPDATE cars SET 
          id = :id, 
          brand = :brand, 
          model = :model, 
          year = :year 
          WHERE id = :oldid";
    $query = $odb->prepare($q);
    $results = $query->execute(array(
            ":id"    => $id,
            ":brand" => $brand,
            ":model" => $model,
            ":year"  => $year,
            ":oldid" => $_GET['id'],
    ));

作为旁注，尽量不要在SQL中放置变量（例如$_GET['id']），使用PDO的部分想法是避免这样做。

让它工作了！

工作代码：

<?php
    require_once("connect.php");
    $query = "SELECT * FROM cars WHERE id = :id";
    $result = $dbh->prepare($query);
    $result->execute(array(':id' => $_REQUEST['id']) );
    while  ($row = $result->fetch(PDO::FETCH_ASSOC)) { ?>
    <h1>Modify a car</h1>
    <form  action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
    Brand:      <input type="text" name="brand" value="<?php echo $row['brand']; ?>"  /><br />
    Model:      <input type="text" name="model" value="<?php echo $row['model']; ?>"  /><br />
    Year:       <input type="text" name="year"  value="<?php echo $row['year'];  ?>"   /><br />
    ID:         <input type="text" name="id"    value="<?php echo $row['id'];  }?>"   /><br />
    <input type="submit" value="Modify" name="submit"/>
    </form>
    <?php
    if(isset($_POST['submit'])) {
    $brand = $_POST['brand'];
    $model = $_POST['model'];
    $year  = $_POST['year'];
    $id    = $_POST['id'];
    $queryupdate = "UPDATE cars SET 
          brand= :brand, model= :model, year= :year WHERE id= :id";
    $q = $dbh->prepare($queryupdate);
    $q->execute(array(
            ":id"    => $id,
            ":brand" => $brand,
            ":model" => $model,
            ":year"  => $year));
            //Send them back to the page they were at/
header("location:admin.php");
    }
?>