此页面使用$_GET获取资产ID并查询mysql数据库并返回一些信息。
如果'id'与任何内容都不匹配，则不会显示任何结果，但页面看起来很好。如果'id'为null，则$id = $_GET["id"] or die(mysql_error());会发生错误。发生这种情况时，页面布局无法正确显示。我该如何解决这个问题？
奖金问题：如果ID与数据库中的任何ID不匹配或为空，我将如何获得“找不到匹配的结果”等消息。
谢谢。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<link rel="stylesheet" type="text/css" href="style.css" />
<title>IT Asset</title>
</head>
<body>
<div id="page">
<div id="header">
<img src="images/logo.png" />
</div>
</div>
<div id="content">
<div id="container">
<div id="main">
<div id="menu">
<ul>
<table width="100%" border="0">
<tr>
<td><li><a href="index.php">Search Assets</a></li></td>
<td><li><a href="browse.php">Browse Assets</a></li></td>
<td><li><a href="add_asset.php">Add Asset</a></li></td>
<td> </td>
</tr>
</table>
</ul>
</div>
<div id="text">
<ul>
<li>
<h1>View Asset</h1>
</li>
</ul>
<table width="100%" border="0" cellpadding="2">
<?php
//make database connect
mysql_connect("localhost", "asset_db", "asset_db") or die(mysql_error());
mysql_select_db("asset_db") or die(mysql_error());
//get asset
$id = $_GET["id"] or die(mysql_error());
//get type of asset
$sql = "SELECT asset.type
From asset
WHERE asset.id = $id";
$result = mysql_query($sql)
or die(mysql_error());
$row = mysql_fetch_assoc($result);
$type = $row['type'];
switch ($type){
case "Server":
$sql = "
SELECT asset.id
,asset.company
,asset.location
,asset.purchase_date
,asset.purchase_order
,asset.value
,asset.type
,asset.notes
,server.manufacturer
,server.model
,server.serial_number
,server.esc
,server.user
,server.prev_user
,server.warranty
FROM asset
LEFT JOIN server
ON server.id = asset.id
WHERE asset.id = $id
";
$result = mysql_query($sql);
while($row = mysql_fetch_assoc($result))
{
echo "<tr><td> </td><td>Asset ID:</td><td>";
$id = $row['id'];
setcookie('id', $id);
echo "$id</td></tr>";
echo "<tr<td> </td><td>Company:</td><td>";
$company = $row['company'];
setcookie('company', $company);
echo "$company</td></tr>";
echo "<tr><td> </td><td>Location:</td><td>";
$location = $row['location'];
setcookie('location', $location);
echo "$location</td></tr>";
echo "<tr><td> </td><td>Purchase Date:</td><td>";
$purchase_date = $row['purchase_date'];
setcookie('purchase_date', $purchase_date);
echo "$purchase_date</td></tr>";
echo "<tr><td> </td><td>Purchase Order:</td><td>";
$purchase_order = $row['purchase_order'];
setcookie('purchase_order', $purchase_order);
echo "$purchase_order</td></tr>";
echo "<tr><td> </td><td>Value:</td><td>";
$value = $row['value'];
setcookie('value', $value);
echo "$value</td></tr>";
echo "<tr><td> </td><td>Type:</td><td>";
$type = $row['type'];
setcookie('type', $type);
echo "$type</td></tr>";
echo "<tr><td> </td><td>Notes:</td><td>";
$notes = $row['notes'];
setcookie('notes', $notes);
echo "$notes</td></tr>";
echo "<tr><td> </td><td>Manufacturer:</td><td>";
$manufacturer = $row['manufacturer'];
setcookie('manufacturer', $manufacturer);
echo "$manufacturer</td></tr>";
echo "<tr><td> </td><td>Model / Description:</td><td>";
$model = $row['model'];
setcookie('model', $model);
echo "$model</td></tr>";
echo "<tr><td> </td><td>Serial Number / Service Tag:</td><td>";
$serial_number = $row['serial_number'];
setcookie('serial_number', $serial_number);
echo "$serial_number</td></tr>";
echo "<tr><td> </td><td>Express Service Code:</td><td>";
$esc = $row['esc'];
setcookie('esc', $esc);
echo "$esc</td></tr>";
echo "<tr><td> </td><td>User:</td><td>";
$user = $row['user'];
setcookie('user', $user);
echo "$user</td></tr>";
echo "<tr><td> </td><td>Previous User:</td><td>";
$prev_user = $row['prev_user'];
setcookie('prev_user', $prev_user);
echo "$prev_user</td></tr>";
echo "<tr><td> </td><td>Warranty:</td><td>";
$warranty = $row['warranty'];
setcookie('warranty', $warranty);
echo "$warranty</td></tr>";
}
break;
case "Laptop":
$sql = "
SELECT asset.id
,asset.company
,asset.location
,asset.purchase_date
,asset.purchase_order
,asset.value
,asset.type
,asset.notes
,laptop.manufacturer
,laptop.model
,laptop.serial_number
,laptop.esc
,laptop.user
,laptop.prev_user
,laptop.warranty
FROM asset
LEFT JOIN laptop
ON laptop.id = asset.id
WHERE asset.id = $id
";
$result = mysql_query($sql);
while($row = mysql_fetch_assoc($result))
{
echo "<tr><td> </td><td>Asset ID:</td><td>";
$id = $row['id'];
setcookie('id', $id);
echo "$id</td></tr>";
echo "<tr<td> </td><td>Company:</td><td>";
$company = $row['company'];
setcookie('company', $company);
echo "$company</td></tr>";
echo "<tr><td> </td><td>Location:</td><td>";
$location = $row['location'];
setcookie('location', $location);
echo "$location</td></tr>";
echo "<tr><td> </td><td>Purchase Date:</td><td>";
$purchase_date = $row['purchase_date'];
setcookie('purchase_date', $purchase_date);
echo "$purchase_date</td></tr>";
echo "<tr><td> </td><td>Purchase Order:</td><td>";
$purchase_order = $row['purchase_order'];
setcookie('purchase_order', $purchase_order);
echo "$purchase_order</td></tr>";
echo "<tr><td> </td><td>Value:</td><td>";
$value = $row['value'];
setcookie('value', $value);
echo "$value</td></tr>";
echo "<tr><td> </td><td>Type:</td><td>";
$type = $row['type'];
setcookie('type', $type);
echo "$type</td></tr>";
echo "<tr><td> </td><td>Notes:</td><td>";
$notes = $row['notes'];
setcookie('notes', $notes);
echo "$notes</td></tr>";
echo "<tr><td> </td><td>Manufacturer:</td><td>";
$manufacturer = $row['manufacturer'];
setcookie('manufacturer', $manufacturer);
echo "$manufacturer</td></tr>";
echo "<tr><td> </td><td>Model / Description:</td><td>";
$model = $row['model'];
setcookie('model', $model);
echo "$model</td></tr>";
echo "<tr><td> </td><td>Serial Number / Service Tag:</td><td>";
$serial_number = $row['serial_number'];
setcookie('serial_number', $serial_number);
echo "$serial_number</td></tr>";
echo "<tr><td> </td><td>Express Service Code:</td><td>";
$esc = $row['esc'];
setcookie('esc', $esc);
echo "$esc</td></tr>";
echo "<tr><td> </td><td>User:</td><td>";
$user = $row['user'];
setcookie('user', $user);
echo "$user</td></tr>";
echo "<tr><td> </td><td>Previous User:</td><td>";
$prev_user = $row['prev_user'];
setcookie('prev_user', $prev_user);
echo "$prev_user</td></tr>";
echo "<tr><td> </td><td>Warranty:</td><td>";
$warranty = $row['warranty'];
setcookie('warranty', $warranty);
echo "$warranty</td></tr>";
}
break;
case "Desktop":
$sql = "
SELECT asset.id
,asset.company
,asset.location
,asset.purchase_date
,asset.purchase_order
,asset.value
,asset.type
,asset.notes
,desktop.manufacturer
,desktop.model
,desktop.serial_number
,desktop.esc
,desktop.user
,desktop.prev_user
,desktop.warranty
FROM asset
LEFT JOIN desktop
ON desktop.id = asset.id
WHERE asset.id = $id
";
$result = mysql_query($sql);
while($row = mysql_fetch_assoc($result))
{
echo "<tr><td> </td><td>Asset ID:</td><td>";
$id = $row['id'];
setcookie('id', $id);
echo "$id</td></tr>";
echo "<tr<td> </td><td>Company:</td><td>";
$company = $row['company'];
setcookie('company', $company);
echo "$company</td></tr>";
echo "<tr><td> </td><td>Location:</td><td>";
$location = $row['location'];
setcookie('location', $location);
echo "$location</td></tr>";
echo "<tr><td> </td><td>Purchase Date:</td><td>";
$purchase_date = $row['purchase_date'];
setcookie('purchase_date', $purchase_date);
echo "$purchase_date</td></tr>";
echo "<tr><td> </td><td>Purchase Order:</td><td>";
$purchase_order = $row['purchase_order'];
setcookie('purchase_order', $purchase_order);
echo "$purchase_order</td></tr>";
echo "<tr><td> </td><td>Value:</td><td>";
$value = $row['value'];
setcookie('value', $value);
echo "$value</td></tr>";
echo "<tr><td> </td><td>Type:</td><td>";
$type = $row['type'];
setcookie('type', $type);
echo "$type</td></tr>";
echo "<tr><td> </td><td>Notes:</td><td>";
$notes = $row['notes'];
setcookie('notes', $notes);
echo "$notes</td></tr>";
echo "<tr><td> </td><td>Manufacturer:</td><td>";
$manufacturer = $row['manufacturer'];
setcookie('manufacturer', $manufacturer);
echo "$manufacturer</td></tr>";
echo "<tr><td> </td><td>Model / Description:</td><td>";
$model = $row['model'];
setcookie('model', $model);
echo "$model</td></tr>";
echo "<tr><td> </td><td>Serial Number / Service Tag:</td><td>";
$serial_number = $row['serial_number'];
setcookie('serial_number', $serial_number);
echo "$serial_number</td></tr>";
echo "<tr><td> </td><td>Express Service Code:</td><td>";
$esc = $row['esc'];
setcookie('esc', $esc);
echo "$esc</td></tr>";
echo "<tr><td> </td><td>User:</td><td>";
$user = $row['user'];
setcookie('user', $user);
echo "$user</td></tr>";
echo "<tr><td> </td><td>Previous User:</td><td>";
$prev_user = $row['prev_user'];
setcookie('prev_user', $prev_user);
echo "$prev_user</td></tr>";
echo "<tr><td> </td><td>Warranty:</td><td>";
$warranty = $row['warranty'];
setcookie('warranty', $warranty);
echo "$warranty</td></tr>";
}
break;
}
?>
</table>
<br />
<br />
<table width="100%" border="0">
<tr>
<td> </td>
<td> </td>
<td> </td>
<td><a href="#">Add Software</a></td>
<td><a href="#">Edit Asset</a></td>
<td><a href="#">Delete Asset</a></td>
</tr>
</table>
</div>
</div>
</div>
<div class="clear"></div>
<div id="footer" align="center">
<p> </p>
</div>
</div>
<div id="tagline">
</div>
</body>
</html>
答案 0 :(得分：5)
当您以这种方式集成代码和标记时，您非常有限。您应采取的方法是运行代码，处理输入并生成合适的输出，然后将其传递给知道如何输出此数据的模板。
然后，您可以在输出任何内容之前检查mysql错误，设置一个变量（如果存在）并输出用户友好的错误消息。如果没有错误，那么您可以遍历数据以显示结果。
如果你只想循环数据一次（首先通过数据集循环然后再在模板循环中构建数组），你可以将mysql结果赋给变量并以这种方式处理它（尽管你在完成之前无法关闭数据库）。除非您尝试在企业应用程序中保存毫秒，或者拥有10个1000行的数据，否则它实际上并没有太大的区别。
无论哪种方式你都选择这样做，那么处理这类案件的唯一方法是“先处理然后再处理”......这为你提供了处理输出的最大灵活性。
答案 1 :(得分：4)
我在这里要粗暴地说：你的代码很乱;这就是为什么PHP得到一个非常糟糕的说唱。你真的应该考虑分离你的PHP和HTML。
主要问题是：
$id = $_GET["id"] or die(mysql_error());
当没有给出id时，你甚至都没有尝试处理这个条件;更不用说mysql_error（）将是一个不适合调用的函数。
相反，您应该使用控制结构来处理未设置id的情况。
if(!isset($_GET['id'])) {
$result = mysql_query($sql);
print '<p>Your search returned ';
print mysql_num_rows($result);
print 'results. </p>';
}
else {
print '<p>An id was not supplied.</p>';
}
答案 2 :(得分：4)
只需浏览代码，您可能需要修复此损坏的<tr>：
echo "<tr<td> </td><td>Company:</td><td>";
^
答案 3 :(得分：3)
您的布局会中断，因为您在输出HTML时会“死”。您的页面将在“查看资源”之后将内容输出到表格，然后如果脚本终止，它将在那里停止，而不是在下面输出单个字符。您最终会输出一个表格开始标记，但不会关闭，也不会关闭任何div，正文或html标记。
您还会发现，任何HTML开始输出后都无法使用setcookie功能。
我建议将PHP逻辑和HTML输出完全分开 - 最好分成单独的文件，或者文件顶部的PHP代码和下面的HTML。执行您的逻辑并首先在PHP中保存变量，然后正常输出所有PHP，只需在必要时包含适当的变量。像这样：
<?php
// connect to the database and run your query here
// save results into an array, something like this:
$rows = array();
while($row = mysql_fetch_assoc($result))
{
// processing with $row here if needed
$rows[] = $row;
}
//rest of PHP code
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<!-- rest of the opening HTML code here -->
<table width="100%" border="0" cellpadding="2">
<?php foreach ( $rows as $row ) : ?>
<tr>
<td>Addet ID:</td>
<td><?php echo $row['id'] ?></td>
</tr>
<tr>
...etc
</tr>
<?php endforeach; ?>
</table>
<!-- rest of the closing HTML code here -->
答案 4 :(得分：2)
您不能只是在页面中间死亡 - 您的页面将不完整且无效。您需要做的是在打开表之前检查您的状况，如果出现错误则输出错误消息html，否则输出错误信息表。自杀永远不是解决方案。