php实现数据库的增删改查

迷南。 2021-09-16 14:50 384阅读 0赞

**1.查询：**

数据的显示，这里就可以嵌入php来进行数据的输出

<!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="100%" border="1" cellpadding="0" cellspacing="0">
    
      <tr>
    
        <td>代号</td>
    
        <td>名称</td>
    
        <td>性别</td>
    
        <td>生日</td>
    
        <td>班级</td>
    
        <td>操作</td>
    
      </tr>
    
     
    
    <?php
    
    $db = new MySQLi("localhost","root","12345678","heiheihei");
    
    //连接数据库
    
    $sql = "select * from student ";
    
    //写sql语句
    
    $r = $db->query($sql);
    
    //执行sql语句返回给r
    
    if($r)//条件
    
    {
    
      while ($attr = $r->fetch_row())
    
      {
    
        $ssex = "";
    
         if($attr[2])
    
         {
    
           $ssex = "男";
    
         }
    
         else
    
           {
    
             $ssex = "女";
    
           }
    
        echo
    
        "
    
     <tr>
    
        <td>{$attr[0]}</td>
    
        <td>{$attr[1]}</td>
    
        <td>{$ssex}</td>
    
        <td>{$attr[3]}</td>
    
        <td>{$attr[4]}</td>
    
    //添加一个单击事件，防止不小心删掉
    
    <td><a onclick=\"return confirm('确定要删除吗？？？')"
    
    href='shanchu.php?sno={$attr[0]}'>删除</a>
    
     <a href='xiugai.php?sno={$attr[0]}'>修改</a> </td> </tr>"; } } ?>
    
     
    
    </table>
    
    <a href="tianjia.php" rel="external nofollow" >添加页面</a>
    
    </body>
    
     
    
    </html>

**2.删除的处理页面**

删除时是链接到删除处理页面的，所以还要写一个删除处理页面：

<?php
    
    $aaa = $_GET ["sno"]; //删除方式使用的get，照旧
    
    $db = new mysqli("localhost","root","12345678","heiheihei");
    
    //连接...
    
    $sql = "delete from student WHERE sno='{$aaa}'";
    
    //写sql语句，sno主键
    
    if($db->query($sql)) //执行sql语句
    
    {
    
      header("location:text.php");
    
    //删完回去表页面
    
    }
    
    else{
    
      echo "删除失败";
    
    }
    
    ?>

来张效果图：

![format_png][]

**3.添加数据：**

点击![format_png 1][]即可进入添加页面

添加页面：

<body>
    
     
    
    <h1>添加</h1>
    
    <form action="add.php" method="post" >
    
      <div>代号:<input type="text" name="sno"/></div>
    
      <div>名字:<input type="text" name="sname"/></div>
    
      <div>性别: <input type="radio" value="1" name="sex" />男
    
        <input type="radio" value="0" name="sex"/>女</div>
    
      <div>日期:<input type="text" name="sbirthday"/></div>
    
    //创建表时性别是用的1或2来表示的，要是进行修改不知道1或2代表了什么，所以就要进行处理，处理成用户能够明白的男和女
    
     
    
      <div>班级:
    
      <select name="class">
    
     
    
      <?php
    
        $db= new MYSQLi("localhost","root","12345678","heiheihei");
    
    //连接...
    
        $sql = " select * from class ";
    
    //写sql...   
    
     
    
        $r = $db->query($sql);
    
    //执行...返回...
    
        while($arr = $r->fetch_row())
    
        {
    
          echo "<option value='{$arr[0]}'>{$arr[1]}</option>";
    
          //添上以后回表页面
    
        }
    
        ?>
    
     
    
      
    
      </select>
    
      </div>
    
      <div><input type="submit" value="添加"/></div>
    
    </form>
    
     
    
    </body>

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：

![format_png 2][]

**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  <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";
    
    }
    
    
    
    
    
    
    
    ?>

修改的效果图：

![format_png 3][]

[format_png]: /images/20210726/5d99476ed515438081545ff8847c505f.png
[format_png 1]: /images/20210726/3f50251e00a741d98226c06704566407.png
[format_png 2]: /images/20210726/cf1b3f6b068f444faf62c8e013c16832.png
[format_png 3]: /images/20210726/9a74f5b83a384f8abbce799d04768ee7.png