PHP 数据库操作

连接数据库

连接数据库常用的函数

mysqli_connect(主机IP,用户名,密码,数据库名,端口号)  // 端口号如果是3306可以省略
mysqli_connect_error():获取连接数据库的错误信息
mysqli_connect_erron():获取连接数据库的错误代码
mysqli_set_charset(连接对象,字符编码)

连接示例:连接失败的例子

<?php 
	
	header('Content-type:text/html;charset=utf-8');
	# 连接数据库
	$conn = @mysqli_connect('localhost','root','Admin123','junglezts','3306');

	# 设置数据库字符编码,这里如果连接失败是无法设置的。
	mysqli_set_charset($conn,'utf8');

	# 如果连接失败
	if(mysqli_connect_error()){
		// 输入错误代号,错误信息。
		echo "错误号:".mysqli_connect_errno(),"<br>";
		echo "错误信息:".mysqli_connect_error();
	}

?>

操作数据库

数据库操作语句,增加、删除、更改的结果返回都是TrueFasle

-- 增加
insert into 表名 (字段1,字段2,字段...) values (字段值1,字段值2,字段值...);
-- 删除,整行伤处数据
delete from 表名 where 字段名 = 字段值 and ...;
-- 更改
update 表名 set 字段名 = '字段值' where 字段名 = 字段值 and ... 

常用的PHP函数

mysqli_query():执行SQL语句
mysqli_query_id():获取插入纪录自动增长的ID
mysqli_affected_rows():受影响的记录数
mysqli_error():SQL语句执行的错误信息
mysqli_errno():SQL语句执行的错误码

执行insert SQL语句

<?php 
	
	# 操作数据库
	$conn = mysqli_connect('localhost','root','Admin123','junglezt','3306');
	# 设置字符编码
	mysqli_set_charset($conn,"utf8");
	# 执行SQL语句
	$sql = "insert into user values (1,'zhangsan','123123')";
	$mysql_resp = mysqli_query($conn,$sql);
	# 查询返回结果
	var_dump($mysql_resp);
?>

成功执行SQL语句

测试函数

<?php 
	
	# 操作数据库
	$conn = mysqli_connect('localhost','root','Admin123','junglezt','3306');
	# 设置字符编码
	mysqli_set_charset($conn,"utf8");
	# 执行SQL语句
	$sql = "insert into user values ( ,'LQL','azt1314')";
	$mysql_resp = mysqli_query($conn,$sql);
	
	if ($mysql_resp){
		echo "自动增长的编号是:".mysqli_insert_id($conn),"<br/>";
		echo "受影响的行数:".mysqli_affected_rows($conn);
	}else{
		echo "SQL查询错误信息:".mysqli_error($conn),"<br/>";
		echo "SQL查询错误码:".mysqli_errno($conn);
	}
?>

操作返回数据函数

mysqli_fetch_row() -- 将对象中的一条数据匹配成索引数组(数字下标),指针下移一条
mysqli_fetch_assoc() -- 将对象中的一条数据匹配成关联数组(字段下标),指针下移一条
mysqli_fetch_array() -- 经对象中的一条数据匹配成索引和关联数组(数字、字段下标各一种),指针下移一条
mysqli_fetch_all() -- 匹配所有
mysqli_num_rows() -- 返回的行数
mysqli_num_fields() -- 返回的列数 
mysqli_free_result() -- 销毁结果集合
mysqli_close() -- 关闭连接

示例:

<?php 
	
	# 连接数据库
	$conn = mysqli_connect('localhost','root','Admin123','junglezt','3306');
	# 设置字符集
	mysqli_set_charset($conn,'utf8');

	# 进行 SQL 查询
	$sql = 'select * from user';
	$result = mysqli_query($conn,$sql);

	# 取出查询中每行的值
	// $row1 = mysqli_fetch_assoc($result);
	// $row2 = mysqli_fetch_row($result);
	// $row3 = mysqli_fetch_array($result);
	// echo "<pre>";
	// print_r($row1);
	// print_r($row2);
	// print_r($row3);

	# 查询返回的行数、列数
	// $row = mysqli_num_rows($result);
	// $list = mysqli_num_fields($result);
	// echo $row,"--",$list;


	循环查询中所有字段的内容
	foreach(mysqli_fetch_all($result) as $resp){
		echo "ID : ".$resp[0]."\n";
		echo "usernmae : ".$resp[1]."\n";
		echo "password : ".$resp[2]."\n";
		echo "\n";
	}	


	# 销毁结果集合
	// mysqli_free_result($result);
	// var_dump($result);
	# 断开连接
	// mysqli_close($conn);
?>

数据库操作之开个玩笑的用户后台管理

conn.php 数据库连接文件

<?php 
	
	# 连接数据库
	$conn = mysqli_connect('localhost','root','Admin123','junglezt','3306') or die('数据库连接失败'.mysqli_connect_error());

?>

index.php:主页

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title>用户管理</title>
	<style type="text/css">
		body{
			background-image: url('./img/bg.jpg');
			background-size: 100% ;
			background-repeat: no-repeat;
		}
		table{
			ackground-color: #00000060;
			border: 1px solid #000000;
			margin: auto;
			margin-top: 10%;
		}
		td{
			padding: 5px;
			border: 1px solid #000000;
		}
		.adduser{
			margin-top: 10px;
			margin-left: 510px;
			font-size: 20px;
		}
	</style>
</head>
<body>
	<?php 
	include "./inc/conn.php";
	$sql = 'select * from user';
	$result = mysqli_query($conn,$sql);
	$link = mysqli_fetch_all($result);
	?>
	
	<table>
		<th>ID</th> <th>用户名</th> <th>密码</th> <th>修改</th> <th>删除</th>
		<?php foreach($link as $resp):?>
			<tr>
				<td><?php echo $resp[0]?></td>
				<td><?php echo $resp[1]?></td>
				<td><?php echo $resp[2]?></td>
				<td><a href="./update.php?user=<?php echo $resp[1]?>"><input type="submit" name="submit" value="修改"></a></td>
				<td><a onclick="if(window.confirm('确定要删除吗?'))location.href='./del.php?id=<?php echo $resp[0]?>'"><input type="submit" name="submit" value="删除"></a></td>
			</tr>
		<?php endforeach;?>
	</table>
	<div>
	<a href="./insert.php"><input type="submit" name="submit" value="创建" class="adduser"></a>
	</div>
</body>
</html>

修改页面:update.php

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title>修改用户信息</title>
</head>
<body>
	<?php 

	include "./inc/conn.php";
	$user = $_GET['user'];
	echo "当前用户是:{$user}";
	?>
	<form action="" method="POST">
		新的用户名:<input type="text" name="new_name"><br>
		旧密码:<input type="password" name="password"><br>
		新密码:<input type="password" name="new_pass"><br>
		<input type="submit" name="修改">
	</form>
	<?php 
	$new_name = $_POST['new_name'];
	$new_pass = $_POST['new_pass'];
	$result = mysqli_query($conn,"select * from user where username='{$user}'");
	@$row_info = mysqli_fetch_row($result);
	if ($row_info[1] == $user){
		if (!empty($new_name) && !empty($new_pass)){
			if ($row_info[2] === $_POST['password']){
			$sql = "update user set username='{$new_name}',password='{$new_pass}' where username='{$user}'";
			$resp = mysqli_query($conn,$sql);
			if ($resp){
				echo "用户名、密码更改成功";
			}else{
				echo "用户名、密码更改失败";
			}
			}else{
				echo "旧密码不一致";
			}
		}else{
			echo "新用户名、密码不能为空";
		}
	}else{
		echo "未找到该用户";	
	}
	?>

</body>
</html>

删除页面:del.php

<?php 


	include "./inc/conn.php";
	$id = $_GET['id'];
	$sql = "delete from user where id={$id}";
	$result = mysqli_query($conn,$sql);
	if ($reuslt == NULL){
		header("location:index.php");
	}else{
		echo "删除失败";
	}
?>

创建用户页面: insert.php

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title>创建用户</title>
</head>
<body>
	<form action="insert.php" method="POST">
		用户名:<input type="text" name="username"><br>
		密码:<input type="password" name="password_new"><br>
		确认密码:<input type="password" name="password_again"><br>
		<input type="submit" name="submit" value="创建用户">
	</form>
	<?php 
	include "./inc/conn.php";
	if (!empty($_POST['submit'])){
		# 获取输入的用户名和密码
		$user = $_POST['username'];
		$pass = $_POST['password_new'];
		# 判断两次输入的密码是否一次
		if (empty($pass)){
			echo "密码不能为空";
		}elseif($pass === $_POST['password_again']){
			# 查询是否存在创建的用户
			$select = mysqli_query($conn,"select * from user where username='{$user}'");
			@$select_row = mysqli_num_rows($select);
			# 判断是否已经创建
			if ($select_row){
				echo "{$user}已存在";
			}else{
				# 获取当前的一共有几个用户
				$result = mysqli_query($conn,'select * from user');
				$row = mysqli_num_rows($result);

				# 进行用户创建
				$sql = "insert into user values ({$row},'{$user}','{$pass}')";
				$resp = mysqli_query($conn,$sql);
				# 如果SQL语句执行成功,用户创建成功
				if ($resp){
					echo "用户创建成功";
				}else{
					echo "用户创建失败";
				}
			}
		}else{
			echo "两次输入的密码不一致";
		}
	}else{
		echo "请输入需要创建的用户和密码";
	}
	?>
</body>
</html>

这里是有SQL注入的,以后可以用来SQL注入的防护,和HTML加CSS的美化的练习,主要的功能都实现了。

posted @ 2022-06-15 18:23  Junglezt  阅读(41)  评论(0编辑  收藏  举报