PDO UPDATE創建新記錄而不是更新記錄

Question

我正在使用以下代碼更新記錄。 不好的是，它沒有更新記錄，但它正在添加一條新記錄。

我究竟做錯了什么？ 我希望它更新記錄而不是創建現在的記錄。

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

Modify.php代碼：

<?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,
    )); 
}
?>

Answer 1

您的SQL應該看起來像這樣：

   $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'],
    ));

作為旁注，盡量不要在SQL中放置變量（比如$ _GET ['id']），使用PDO的一部分原則是避免這樣做。

Answer 2

搞定了！

工作代碼：

<?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");
    }

?>