PHP访问MySql数据库实现增删改查功能详解

<?php 
//造连接对象
$db = new MySQLi("localhost","root","","0710_test");

//写SQL语句
$sql = "select * from student";
//检测连接数据库是否成功，失败返回“连接失败”，并退出程序 
if(mysqli_connect_error()){
 die("连接失败"); 
}
//执行SQL语句,返回结果集对象
$result = $db->query($sql);
var_dump($result->num_rows);
//判断结果有无数据
if($result->num_rows){
 echo "存在数据";
}
//取数据（查询语句）
//$arr = $result->fetch_all();//获取所有数据并以二维数组存在
//$arr = $result->fetch_all(MYSQLI_ASSOC);//获取所有数据中的关联数组
//$arr = $result->fetch_array();

//while循环遍历数组所有数据
while($arr = $result->fetch_array()){
 var_dump($arr);
}

//$arr = $result->fetch_assoc();//返回关联数组
//$arr = $result->fetch_object();//列名对应成员变量
//$arr = $result->fetch_row();//返回索引数组
//var_dump($arr);
 
//增删改语句
//添加一条数据(返回值true或false)
$sql = "insert into student values(&#39;102&#39;,&#39;王某&#39;,&#39;男&#39;,&#39;1987-7-1&#39;,&#39;95033&#39;)";
//删除一条数据(返回值true或false)
$sql = "delete from student where Sname=&#39;李军&#39;";
$r = $db->query($sql);
var_dump($r);
?>

<?php 
$db = new MySQLi("localhost","root","","0710_info");
if(mysqli_connect_error()){
 die("连接失败");
}
$sql = "insert into work values(0,&#39;P005&#39;,&#39;2005-01-01&#39;,&#39;2010-10-1&#39;,&#39;山师大&#39;,&#39;教育部&#39;,2)";
if($db->query($sql)){
 echo "添加成功";
 //插入这条数据的id(常用)
 echo $db->insert_id;
}else{
 echo "添加失败";
}
?>