我需要创建一个下拉框，它从数据库中收集记录以填充下拉列表。When one of the values is selected, a form is to be displayed which contains the data relating to the value selected.
表单是具有显示选中数据的功能，同时也是在填写和提交时更新数据库中的记录。
我创建了一个 php 文件来尝试完成此操作，但我收到诸如未定义索引和未知列之类的错误。
我只是 PHP 新手，所以这对我来说是一项艰巨的任务。有人可以看看我的代码并告诉我是否有任何错误。
我一直试图从网上到处拼凑代码，但要让它全部工作起来很棘手。
经过一些调整，我现在没有收到任何错误，但记录不会更新。我收到“记录更新成功”消息，但记录未更新。
我很确定缺少记录更新归结为没有通过正确收集 ID$q=$row["BearId"]但如果我使用$q=$_GET["q"]我只会得到错误。我并不完全肯定这是问题所在，这就是我在这里提出问题的原因。
我将不胜感激您可以提供的任何帮助。我已经用这个东西到目前为止，但我不能让它更新记录。
编辑：我已将问题归结为 id
$sql = "UPDATE //snip WHERE BearId = '$q'";
$q=$row["BearId"];
如果我手动更改BearId为相等'1'，则记录将更新。
更新熊.php
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Update Bears</title>
<script>
function showUser(str)
{
if (str=="")
{
document.getElementById("result").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{
xmlhttp=new XMLHttpRequest();
}
else
{
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("result").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","getvalues.php?q="+str,true);
xmlhttp.send();
}
</script>
<style>
// style elements
</style>
</head>
<body>
<h1>Update Bears</h1>
Select a Bear:
<br />
<select name="bears" onchange="showUser(this.value)">
<option value="">Select a BearId</option>
<?php
$query = "SELECT * FROM bears";
$mysqli = new mysqli('localhost','User','123','bears');
$result = $mysqli->query($query);
while($row = $result->fetch_assoc())
echo '<option value="'.$row["BearId"].'">'.$row["BearId"].'</option>';
?>
</select>
<br />
<?php
$q=$row["BearId"];
$mysqli = new mysqli('localhost','User','123','bears');
$sql = "SELECT * FROM bears WHERE BearId='".$q."'";
if(array_key_exists('_submit_check', $_POST))
{
$weight = $_POST['Weight'];
$sex = $_POST['Sex'];
$type = $_POST['Type'];
$colour = $_POST['Colour'];
$breed = $_POST['BreedId'];
$sql = "UPDATE bears SET Weight = '$weight', Sex = '$sex', Type = '$type', Colour = '$colour', Breed = '$breed' WHERE BearId = '$q'";
if($mysqli->query($sql) === TRUE)
{
echo 'Record updated successfully<br />';
}
else
{
echo $sql.'<br />' . $mysqli->error;
}
$mysqli->close();
}
?>
<br />
<div id="result"></div>
<br />
<a href="insertbear.php" class="Task2">Click here to Visit Task 2 (Insert Bears)</a> | <a href="displaybears.php" class="Task3">Click here to Visit Task 3 (Display Bears)</a>
</body>
</html>
获取值.php
<?php
$q=$_GET["q"];
$mysqli = new mysqli('localhost','User','123','bears');
$sql = "SELECT * FROM bears WHERE BearId='".$q."'";
if($stmt = $mysqli->prepare($sql))
{
$stmt->execute();
$stmt->bind_result($BearId, $Weight, $Sex, $Type, $Colour, $Breed);
while ($stmt->fetch())
{
echo "<form method='post' name='form1' onsubmit='return validateForm()' action='updatebears.php'>";
echo "<p>";
echo "<label for='BreedId'>BreedId:</label>";
echo "<br />";
echo "<select id='BreedId' name='BreedId' />";
echo "<option value='".$Breed."'>".$Breed."</option>";
echo "<option value='1'>1. Polar</option>";
echo "<option value='2'>2. Brown</option>";
echo "<option value='3'>3. Panda</option>";
echo "</select>";
echo "</p>";
echo "<p>";
echo "<label for='Weight'>Weight(kg):</label>";
echo "<br />";
echo "<input type='text' id='Weight' name='Weight' value='".$Weight."' />";
echo "</label>";
echo "</p>";
echo "<p>";
echo "Sex: ";
echo "<br />";
echo "<label for='M'>Male</label><input type='radio' id='M' value='M' name='Sex'";
if($Sex=='M') echo "checked";
echo "/>";
echo "<label for='F'>Female</label><input type='radio' id='F' value='F' name='Sex'";
if($Sex=='F') echo "checked";
echo "/>";
echo "</p>";
echo "<p>";
echo "<label for='Type'>Type:</label> ";
echo "<br />";
echo "<input type='text' id='Type' name='Type' maxlength='100' value='".$Type."' />";
echo "</p>";
echo "<p>";
echo "<label for='Colour'>Colour:</label>";
echo "<br />";
echo "<input type='text' id='Colour' name='Colour' maxlength='20' value='".$Colour."' />";
echo "</p>";
echo "<p>";
echo "<input type='submit' value='Submit' />";
echo "<input type='reset' value='Reset' />";
echo "<input type='hidden' name='_submit_check' value=1 />";
echo "</p>";
echo "</form>";
}
}
else
{
echo 'Unable to connect';
exit();
}
?>
谢谢您的帮助。