案例1：查询select
使用php连接数据库class9,
获取数据库的表student中的信息，
然后输出到页面上（用表格套住）
1 <?php 2 header("Content-type:text/html; charset=utf-8"); 3 // 建立mysql的链接 4 // 参数：主机名，用户，密码，需要的数据库 5 /* 6 在PHP函数方法前面加@符号，表示忽略警告 7 */ 8 $conn =@mysqli_connect("localhost","root","","lanou0322"); 9 // 判断数据库链接是否成功 10 /*if($conn){ 11 echo "成功了!"; 12 }else{ 13 echo "失败了!"; 14 } 15 */ 16 if(!$conn){ 17 echo "失败"; 18 // 终止 19 exit; 20 } 21 $conn->query('set names utf8'); 22 $sql ="SELECT * FROM student"; 23 $result = $conn->query($sql); 24 // 5.判断 25 // mysqli_num_rows 返回的条数 26 // echo mysqli_num_rows($result); 27 if(mysqli_num_rows($result)>0){ 28 echo "<table border=1>"; 29 echo "<tr> 30 <th>id</th> 31 <th>name</th> 32 <th>sex</th> 33 <th>age</th> 34 </tr>"; 35 while($row = $result -> fetch_assoc()){ 36 echo "<tr> 37 <td style='20'>{$row['id']}</td> 38 <td style='80; text-align:center;'>{$row['name']}</td> 39 <td style='20'>{$row['sex']}</td> 40 <td style='20'>{$row['age']}</td> 41 </tr>"; 42 } 43 echo "</table>"; 44 //如果想在一个页面输出同样的两个数据库表格那么可以在执行一次$conn->query($sql);然后打印 45 echo "<hr/>"; 46 $result = $conn->query($sql); 47 echo "<table border=1>"; 48 echo "<tr> 49 <th>id</th> 50 <th>name</th> 51 <th>sex</th> 52 <th>age</th> 53 </tr>"; 54 while($row = $result -> fetch_assoc()){ 55 echo "<tr> 56 <td style='20'>{$row['id']}</td> 57 <td style='80; text-align:center;'>{$row['name']}</td> 58 <td style='20'>{$row['sex']}</td> 59 <td style='20'>{$row['age']}</td> 60 </tr>"; 61 } 62 echo "</table>"; 63 } 64 // 关闭数据库 65 $conn->close();//关闭数据库 66 67 ?>
效果：
案例2：插入insert
使用php连接数据库
1. 向数据表student,插入一条信息："小明", 28, "男" 添加成功输出提示"添加成功"
2. 插入多条信息
1 <?php 2 header("Content-type:text/html;charset=utf-8"); 3 //链接数据库 4 $conn =@mysqli_connect("localhost","root","","lanou0322"); 5 if(!$conn){ 6 echo "失败"; 7 // 终止 8 exit; 9 } 10 $conn->query('set names utf8'); 11 //向数据库添加数据INSERT INTO name(数据表名) VALUE （添加的数据信息）; 12 $sql ="INSERT INTO student(name,sex,age) VALUES ('小黄','女','17')"; 13 $sql ="SELECT * FROM student"; 14 $result = $conn->query($sql); 15 // 判断插入是否成功 16 // 使用 mysqli_affected_rows($conn); 17 if(mysqli_affected_rows($conn)>0){ 18 echo "成功"; 19 }else{ 20 echo "失败"; 21 } 22 echo mysqli_num_rows($result); 23 if(mysqli_num_rows($result)>0){ 24 echo "<table border=1>"; 25 echo "<tr> 26 <th>id</th> 27 <th>name</th> 28 <th>sex</th> 29 <th>age</th> 30 </tr>"; 31 while($row = $result -> fetch_assoc()){ 32 echo "<tr> 33 <td style='20'>{$row['id']}</td> 34 <td style='80; text-align:center;'>{$row['name']}</td> 35 <td style='20'>{$row['sex']}</td> 36 <td style='20'>{$row['age']}</td> 37 </tr>"; 38 } 39 echo "</table>"; 40 } 41 $conn->close();//关闭数据库 42 ?>
效果：
案例3：更新update
使用php连接数据库
更新(修改)数据表student中，年龄age=28的改为10
1 <?php 2 header("Content-type:text/html;charset=utf-8"); 3 $conn =@mysqli_connect("localhost","root","","lanou0322"); 4 $conn->query('set names utf8'); 5 // mysqli_query($conn,"UPDATA name SET... WHERE ...") 6 $sql = mysqli_query($conn,"UPDATE student SET name = '我傻逼',age = '10' WHERE id = 1"); 7 $sql ="SELECT * FROM student"; 8 $result = $conn->query($sql); 9 echo mysqli_affected_rows($conn); 10 // 判断修改是否成功 11 if(mysqli_affected_rows($conn)>0){ 12 echo "成功"; 13 }else{ 14 echo "失败"; 15 } 16 echo mysqli_num_rows($result); 17 if(mysqli_num_rows($result)>0){ 18 echo "<table border=1>"; 19 echo "<tr> 20 <th>id</th> 21 <th>name</th> 22 <th>sex</th> 23 <th>age</th> 24 </tr>"; 25 while($row = $result -> fetch_assoc()){ 26 echo "<tr> 27 <td style='20'>{$row['id']}</td> 28 <td style='80; text-align:center;'>{$row['name']}</td> 29 <td style='20'>{$row['sex']}</td> 30 <td style='20'>{$row['age']}</td> 31 </tr>"; 32 } 33 echo "</table>"; 34 } 35 $conn->close(); 36 ?>
效果：
案例4：删除delete
使用php连接数据库class9,
删除数据库的表student中，id号为1的数据
1 <?php 2 header("Content-type:text/html;charset=utf-8"); 3 $conn =@mysqli_connect("localhost","root","","lanou0322"); 4 $conn->query('set names utf8'); 5 $sql = mysqli_query($conn,"DELETE FROM student WHERE id = 1"); 6 $sql ="SELECT * FROM student"; 7 $result = $conn->query($sql); 8 // echo mysqli_affected_rows($conn); 9 // 判断修改是否成功 10 if(mysqli_affected_rows($conn)>0){ 11 echo "成功"; 12 }else{ 13 echo "失败"; 14 } 15 // echo mysqli_num_rows($result); 16 if(mysqli_num_rows($result)>0){ 17 echo "<table border=1>"; 18 echo "<tr> 19 <th>id</th> 20 <th>name</th> 21 <th>sex</th> 22 <th>age</th> 23 </tr>"; 24 while($row = $result -> fetch_assoc()){ 25 echo "<tr> 26 <td style='20'>{$row['id']}</td> 27 <td style='80; text-align:center;'>{$row['name']}</td> 28 <td style='20'>{$row['sex']}</td> 29 <td style='20'>{$row['age']}</td> 30 </tr>"; 31 } 32 echo "</table>"; 33 } 34 $conn->close(); 35 ?>
效果：
