PHP无法写入MySQL数据库

Question

我已经检查了我的代码很多很多次，并添加了任何缺少的括号或分号，但每当我将此代码上传到我的网站并加载页面时，我仍然得到一个完全空白的屏幕。该代码来自 O'Reilly 的一本书籍，所以我去检查了网站，看看书中是否有任何报告的错误，但没有发现与这个特定示例相关的任何内容。

我不认为这是权限问题，因为我认为该页面至少会报告我编码到其中的错误之一。这可能与我使用的 PHP 或 MySQL 版本有关吗？我过去能够连接到数据库并查询它，但写入却没有发生。我现在完全不知所措。我想做的就是写入我的 MySQL 数据库和派对:(

这是代码:

    <?php
    require_once 'login.php';

    // Create connection
    $db_server = mysql_connect($db_hostname, $db_username, $db_password);

    // Check connection
    if (!$db_server) die("Unable to connect  to MySQL: " . mysql_error());

    mysql_select_db($db_database, $db_server)
        or die("Unable to select database: " . mysql_error());

    if (isset($_POST['delete']) && isset($_POST['avail']))
    {
        $avail = get_post('avail');
        $query = DELETE FROM test WHERE avail='$avail';

        if (!mysql_query($query, $db_server))
            echo "DELETE failed: $query<br />" .
            mysql_error() . "<br /><br />";
    }       

    if (isset($_POST['id']) &&
        isset($_POST['item_name']) &&
        isset($_POST['avail']))
    {
        $id         = get_post('id');
        $item_name  = get_post('item_name');
        $avail      = get_post('avail');

    $query = "INSERT INTO test VALUES" .
            "('$id','$item_name','$avail')";

    if (!mysql_query($query, $db_server))
        {echo "INSERT failed: $query<br />" .
        mysql_error() . "<br /><br />";
    }
    }

    ?>
    <form action="index.php" method="post"><pre>
        Line Number         <input type="text" name="id" />
        Product Name        <input type="text" name="item_name" />
        Quantity Available  <input type="text" name="avail" />
        <input type="submit" value="ADD RECORD" />
    </pre></form>
    <?php


    $query  = "SELECT * FROM test";
    $result = mysql_query($query);

    if (!$result) die ("Database access failed: " . mysql_error());
    $rows = mysql_num_rows($result);

    for ($j = 0 ; $j < $rows ; ++$j)
    {
        $row = mysql_fetch_row($result);
        ?>
    <pre>
        Line Number $row[0]
        Product Name $row[1]
        Quantity Available $row[2]
    </pre>
    <form action="index.php" method="post">
    <input type="hidden" name="delete" value="yes" />
    <input type="hidden" name="avail" value="$row[2]" />
    <input type="submit" name="DELETE RECORD" /></form>
    <?php
    }

    mysql_close($db_server);

    function get_post($var)
    {
        return mysql_real_escape_string($_POST[$var]);
    }



    ?>      

Answer 1

您的删除语句有错误，请尝试以下代码:

 <?php
    require_once 'login.php';

    // Create connection
    $db_server = mysql_connect($db_hostname, $db_username, $db_password);

    // Check connection
    if (!$db_server) die("Unable to connect  to MySQL: " . mysql_error());

    mysql_select_db($db_database, $db_server)
        or die("Unable to select database: " . mysql_error());

    if (isset($_POST['delete']) && isset($_POST['avail']))
    {
        $avail = get_post('avail');
        $query = "DELETE FROM test WHERE avail='$avail'";

        if (!mysql_query($query, $db_server))
            echo "DELETE failed: $query<br />" .
            mysql_error() . "<br /><br />";
    }       

    if (isset($_POST['id']) &&
        isset($_POST['item_name']) &&
        isset($_POST['avail']))
    {
        $id         = get_post('id');
        $item_name  = get_post('item_name');
        $avail      = get_post('avail');

    $query = "INSERT INTO test VALUES" .
            "('$id','$item_name','$avail')";

    if (!mysql_query($query, $db_server))
        {echo "INSERT failed: $query<br />" .
        mysql_error() . "<br /><br />";
    }
    }

    ?>
    <form action="index.php" method="post"><pre>
        Line Number         <input type="text" name="id" />
        Product Name        <input type="text" name="item_name" />
        Quantity Available  <input type="text" name="avail" />
        <input type="submit" value="ADD RECORD" />
    </pre></form>
    <?php


    $query  = "SELECT * FROM test";
    $result = mysql_query($query);

    if (!$result) die ("Database access failed: " . mysql_error());
    $rows = mysql_num_rows($result);

    for ($j = 0 ; $j < $rows ; ++$j)
    {
        $row = mysql_fetch_row($result);
        ?>
    <pre>
        Line Number $row[0]
        Product Name $row[1]
        Quantity Available $row[2]
    </pre>
    <form action="index.php" method="post">
    <input type="hidden" name="delete" value="yes" />
    <input type="hidden" name="avail" value="$row[2]" />
    <input type="submit" name="DELETE RECORD" /></form>
    <?php
    }

    mysql_close($db_server);

    function get_post($var)
    {
        return mysql_real_escape_string($_POST[$var]);
    }



    ?>