添加也需要一个处理页面来判断添加：
<?php
$sno = $_POST["sno"];
//$_POST 变量用于收集来自 method="post" 的表单中的值。
$sname = $_POST["sname"];
$ssex = $_POST["ssex"];
$sbirthday = $_POST["sbirthday"];
$class = $_POST["class"];
$db = new mysqli("localhost","root","12345678","heiheihei");
$sql = "insert into student VALUES ('{$sno}','{$sname}','{$ssex}','{$sbirthday}','{$class}')";
//向数据库中添加写的数据
if($db->query($sql))
{
header("location:text.php");
//header() 函数向客户端发送原始的 HTTP 报头。
}
else {
echo "添加失败";
}
?>
效果图：
4.修改数据：主键不可修改！！
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>
<body>
<h1>修改</h1>
<?php
$sno = $_GET{"sno"};
$db = new mysqli("localhost","root","12345678","heiheihei");
$sql = "select * from student WHERE sno='{$sno}'";
$r = $db->query($sql);
$arr = $r->fetch_row();
?>
<form action="update.php" method="post">
<div>代号：<input readonly="readonly" type="text" name="sno" value="<?php
echo $arr[0];
?>"/></div>
//readonly只可读
<div>名称：<input type="text" name="sname" value="<?php echo $arr[1]; ?>"/></div> <div>性别： <input type="radio" name="ssex" value="1" <?php echo $arr[2]?"checked='checked'":""; ?>/>男 <!-- 三元运算符，如果性别=ture，默认值就在男上面，否则空--> <input type="radio" name="ssex" value="0" <?php echo $arr[2]?"":"checked='checked'"; ?>/>女 </div> <div>日期：<input type="text" name="sbirthday" value="<?php echo $arr[3]; ?>"/></div> <div>班级：<select name="class">
//value取默认值
<?php
$sclass = "select * from class";
$rclass = $db->query($sclass);
while($attr = $rclass->fetch_row())
//取到的班级信息
{
//判断将要输出的班级是不是和该人员的是否相同
if($arr[4]==$attr[0])//arr是班级名，attr是班级的代号，俩表
{
echo "<option value = '{$attr[0]}' selected='selected'>{$attr[1]}</option>";
}
else{
echo "<option value = '{$attr[0]}'>{$attr[1]}</option>";
}
}
?>
</select></div>
<div><input type="submit" value="修改完毕"/></div>
</form>
</body>
</html>
]
修改的处理页面：
<?php
$sno = $_POST["sno"];
$sname = $_POST["sname"];
$ssex = $_POST["ssex"];
$sbirthday = $_POST["sbirthday"];
$class = $_POST["class"];
$db = new mysqli("localhost","root","12345678","heiheihei");
$sql = "update student set sname='{$sname}',
ssex='{$ssex}',
sbirthday='{$sbirthday}',
class='{$class}' WHERE sno='{$sno}'";
//看一下是不是传递过来的sno值；
if($db->query($sql))
{
header("location:text.php");
}
else{
echo "修改失败";
}
?>
