PHP+MySQL删除操作实例

<h1>删除记录</h1>?
<?php?
??? //连接数据库的参数?
??? $host = "localhost";?
??? $user = "root";?
??? $pass = "zq19890319";?
??? $db = "phpdev";?
??? //创建mysqli对象?
??? //打开一个数据库连接?
??? $mysqli = new mysqli($host,$user,$pass,$db);?
??? //检查连接错误?
??? if(mysqli_connect_errno()){?
??????? die("Unable to connect!");?
??? }?
??? //如果记录ID存在,则执行删除操作?
??? if(isset($_GET['id'])){?
??????? //构造删除记录的SQL?
??????? $query = "DELETE FROM symbols WHEREid = ".$_GET['id'];?
?????????
??????? //执行SQL查询?
??????? if($mysqli->query($query)){?
??????????? //显示删除后影响的记录数?
??????????? echo $mysqli->affected_rows. "row(s) affected";?
??????? }?
??????? else?
??????? {?
??????????? //如果没有匹配的记录,显示数据库返回的错误信息?
??????????? echo "Error in query : $query. ".$mysqli->error;?
??????? }?
??? }?
??? //构造显示删除后的记录?
??? $query = "SELECT * FROM symbols";?
??? //执行该查询?
??? if($result=$mysqli->query($query)){?
??????? //显示返回的记录集行数?
??????? if($result->num_rows>0){?
??????????? //如果有记录?
??????????? //显示记录集中列的内容?
??????????? echo "<table cellpadding=10 border=1>";?
??????????? while($row=$result->fetch_array()){?
??????????????? echo "<tr>";?
??????????????? echo "<td>".$row[0]."</td>";?
??????????????? echo "<td>".$row[1]."</td>";?
??????????????? echo "<td>".$row[2]."</td>";?
??????????????? echo "<td><a href=".$_SERVER['PHP_SELF']." mce_href=".$_SERVER['PHP_SELF']."?id=".$row[0].">删除</a></td>";?
??????????????? echo "</tr>";?
??????????? }?
??????? }?
??????? //释放对象所占用的内存?
??????? $result->close();?
??? }?
??? else?
??? {?
??????? //输出数据库错误的信息?
??????? echo "Error in query: $query. ".$mysqli->error;?
??? }?
??? //关闭数据库?
??? $mysqli->close();?
?>