Detailed explanation of PHP access to MySql database to implement addition, deletion, modification and query functions

The following editor will bring you an example of logical operations and additions, deletions, modifications and queries using PHP to access the MySql database. The editor thinks it’s pretty good, so I’ll share it with you now and give it as a reference. Let’s follow the editor to take a look

PHP access MySql database

<?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);
?>

Examples of additions, deletions, and modifications of self-increasing lists in the database

<?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";
}
?>

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