PHP MySQLi 增删改查
最近几天，我们一直在学习利用MySQLi访问数据库并对其中的数据进行操作。今天给大家展现一个完整的例子，我们来制作一个新闻发布系统，利用MySQLi来操作数据库，实现对新闻的添加、修改、删除、查询等基本功能。（以下代码分为前端显示和后台php处理代码，中间用空行隔开，注意区分）
1、登陆页面：这由本公司内部人员通过员工号和身份证号才能登陆，代码如下：
//前端显示部分
<!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>无标题文档</title>
</head>
<body>
<h2>管理员登陆</h2>
<form action="dlyz.php" method="post">
<div>用户名：<input type="text" name="user" value="请输入您的工号" /></div>
<br />
<div>密 码：<input type="password" name="psd" /></div>
<br />
<input type="submit" value="登录" />
<input type="submit" value="注册新用户" formaction="zhuc.php"/>
</form>
</body>
</html>
//php代码对提交登陆的信息进行处理
<?php
$user = $_POST["user"];
$psd = $_POST["psd"];
//造对象
$db = new MySQLi("localhost","root","","newssystem");
//判断是否出错
!mysqli_connect_error() or die("连接失败！！");
//写sql语句
$sql = "select psd from yonghu where user='{$user}'";
//执行SQL语句
$result = $db-> query($sql);
$v = $result->fetch_row();
if($psd==$v[0])
{
header("location:fabuxinwen.php");
}
else
{
echo"您输入的用户名或密码不正确，请重新输入！！";
}
2、注册页面：公司/报社来了新员工，只有注册后才能登陆
<!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>无标题文档</title>
</head>
<body>
<h2>欢迎注册</h2>
<body>
<form action="zhucyz.php"method="post">
<div>用户名：<input type="text" name="user" value="请输入您的工号"/></div><br />
<div>密 码：<input type="password" name="psd" /></div><br />
<input type="submit" value="提交" />
</form>
</body>
</html>
<?php
$user = $_POST["user"];
$psd = $_POST["psd"];
//造对象
$db = new MySQLi("localhost","root","","newssystem");
//判断是否出错
!mysqli_connect_error() or die("连接失败！！");
//写sql语句
$sql = "insert into yonghu values('{$user}','{$psd}')";
//执行SQL语句
$result = $db-> query($sql);
if($result)
{
header("location:dl.php");
}
else
{
echo"很抱歉，注册失败！！";
}
3、登陆进去以后，是发布新闻页面，点击提交按钮进行提交保存到已经建立好的数据库，点击查看按钮进行查看确认
<!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>无标题文档</title>
</head>
<body>
<div style="width:100%; text-align:center" >
<h2>发布新闻</h2>
<form method="post">
<input type="hidden" name="newsid"/>
<table style="margin:0 auto; text-align:left" >
<tr>
<td >标题：</td><td><input type="text" style="width:400px" name="title" /></td>
</tr>
<tr>
<td >作者：
</td><td><input type="text" style="width:400px" name="Author" /></td>
</tr>
<tr>
<td >来源：</td><td><input type="text" style="width:400px" name="source"/></td>
</tr>
<tr>
<td >内容：</td>
<td><textarea cols="auto" rows="auto" style="width:400px; height:400px" name="content"></textarea></td>
</tr>
</table><br />
<?php
$time = date('y-m-d h:i:s');
echo "<input type=\"hidden\" name=\"time\" value=\"{$time}\"/>";
?>
<input type="submit" value="提交" formaction="tijiao.php"/>
<input type="submit" value="查看" formaction="chakan.php"/>
</form>
</div>
</body>
</html>
<?php
$title = $_POST["title"];
$Author = $_POST["Author"];
$source = $_POST["source"];
$content = $_POST["content"];
//造对象
$db = new MySQLi("localhost","root","","newssystem");
//判断是否出错
!mysqli_connect_error() or die("添加失败！！");
//写sql语句
$sql = "insert into news(title,Author,source,content) values('{$title}','{$Author}','{$source}','{$content}')";
//执行SQL语句
$result = $db-> query($sql);
if($result)
{
header("location:fabuxinwen.php");
}
else
{
echo"很抱歉，添加失败！！";
}
4、查看页面
<!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>无标题文档</title>
</head>
<body>
<table width="70%" border="1px" cellpadding="0" cellspacing="0" style="text-align:center">
<tr>
<td>编号</td>
<td>标题</td>
<td>作者</td>
<td>来源</td>
<td>日期</td>
<td>删除</td>
<td>修改</td>
</tr>
<?php
$db=new mysqli("localhost","root","","newssystem");
!mysqli_connect_error() or die("连接错误");
$sql="select * from news";
$result=$db->query($sql);
while($attr=$result->fetch_row())
{
echo "
<tr>
<td>{$attr[0]}</td>
<td>{$attr[1]}</td>
<td>{$attr[2]}</td>
<td>{$attr[3]}</td>
<td>{$attr[5]}</td>
<td><a onclick=\" return confirm('确定删除')\" href='scchuli.php?newsid={$attr[0]}'>删除</a></td>
<td><a href='xiugai.php?newsid={$attr[0]}'>修改</a></td>
</tr>
";
}
?>
</table>
</body>
</html>
5、在查看页面可以进行相关内容的修改和删除
//修改：在点击修改按钮后，会跳转到修改页面，此时会显示出之前已经发布的内容、标题等相关内容
<!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>无标题文档</title>
</head>
<body>
<?php
$id = $_GET["newsid"];
$db=new mysqli("localhost","root","","newssystem");
!mysqli_connect_error() or die("连接错误");
$sql="select * from news where newsid='{$id}'";
$result=$db->query($sql);
$attr=$result->fetch_row();
?>
<div style="width:100%; text-align:center" >
<h2>修改新闻</h2>
<form action="xgchuli.php" method="post">
<input type="hidden" name="newsid" <?php echo "value='{$attr[0]}'";?>/>
<table style="margin:0 auto; text-align:left" >
<tr>
<td >标题：</td><td><input type="text" style="width:400px" name="title" <?php echo "value='{$attr[1]}'";?>/></td>
</tr>
<tr>
<td >作者：
</td><td><input type="text" style="width:400px" name="Author" <?php echo "value='{$attr[2]}'";?>/>
</td>
</tr>
<tr>
<td >来源：</td><td><input type="text" style="width:400px" name="source" <?php echo "value='{$attr[3]}'";?>/>
</td>
</tr>
<tr>
<td >内容：</td>
<td><textarea cols="auto" rows="auto" style="width:400px; height:400px" name="content"><?php echo "{$attr[4]}";?>
</textarea></td>
</tr>
</table><br />
<?php
$time = date('y-m-d h:i:s');
echo "<input type=\"hidden\" name=\"time\" value=\"{$time}\"/>";
?>
<div><a href="chakan.php"><input type="button" title="查看" value="查看" /></a><input type="submit" title="修改" value="修改"/>
</div>
</form>
</body>
</html>
<?php
$id=$_POST["newsid"];
$title=$_POST["title"];
$Author=$_POST["Author"];
$source=$_POST["source"];
$content=$_POST["content"];
$time=$_POST["time"];
$db = new MySQLi("localhost","root","","newssystem");
!mysqli_connect_error() or die("连接失败");
$sql="update news set title='{$title}',Author='{$Author}',source='{$source}',content='{$content}',time='{$time}' where newsid='{$id}' ";
$result=$db->query($sql);
if ($result)
{
header("location:chakan.php");
}
else
{
echo "修改失败";
}
//删除：如果要删除一条新闻，在点击删除按钮之后，不会跳转到任何前台显示页面，只会在后台通过php代码进行相关处理
<?php
$id=$_GET["newsid"];
$db=new mysqli("localhost","root","","newssystem");
!mysqli_connect_error() or die("连接失败");
$sql="delete from news where newsid='{$id}'";
$result=$db->query($sql);
if ($result)
{
header("location:chakan.php");
}
else
{
echo "删除失败";
}
6、修改完成之后，点击页面下方的修改按钮进行提交，在这里也不会有相关的前端显示页面，只是在后台利用相关php代码进行相应处理，成功后返回发布新闻页面
<?php
$title = $_POST["title"];
$Author = $_POST["Author"];
$source = $_POST["source"];
$content = $_POST["content"];
//造对象
$db = new MySQLi("localhost","root","","newssystem");
//判断是否出错
!mysqli_connect_error() or die("添加失败！！");
//写sql语句
$sql = "insert into news(title,Author,source,content) values('{$title}','{$Author}','{$source}','{$content}')";
//执行SQL语句
$result = $db-> query($sql);
if($result)
{
header("location:fabuxinwen.php");
}
else
{
echo"很抱歉，添加失败！！";
}
