How to connect PHP to MySQL

php connects to the MySQL database through the following steps: setting the server address, username and password; generating a connection and selecting the database to operate; executing database queries; closing the database

When using PHP code to operate a MYSQL database, the first thing to do is to connect to the MYSQL database. Today I will introduce to you how to use PHP to connect to the database. It has certain

reference value. I hope it will be helpful to everyone.

##[Recommended course: PHP Tutorial]

1. Connect to the MySQL database

First you need the MySQL server address, user name, password and database name. First we create a demo.php file to write program code. This way we can open the file in the browser. If you encounter an error, it is possible that the user name or password or database name is entered incorrectly.

 $server="localhost";//主机
 $db_username="root";//你的数据库用户名
 $db_password="root";//你的数据库密码

2. Generate a connection and select the database that needs to be operated

Create the variable $db and specify it as the connection string , which is convenient for use in the following code. If an error occurs on the page, a prompt message will be returned indicating that it cannot connect to the database. If successful, PHP successfully connects to the database

//生成一个连接
 $db_connect=mysql_connect($dbhost,$username,$userpass) or die("Unable to connect to the MySQL!");
 //选择一个需要操作的数据库
  mysql_select_db('new',$db_connect);

3. Execute database query

mysql query actually is executed in the body of the html page, so additional PHP opening and closing tags are required. For the query, we will specify to read all fields in the given table. The $query variable selects all rows in the table. So you need to use your table name. In this example, the query is the id and name values ​​​​in the user table

 //执行MySQL语句
  $result=mysql_query("SELECT id,name FROM user");
//提取数据
$row=mysql_fetch_row($result);

## 4. Close the database

After the database execution is completed, the database must be closed

mysqli_close($db);

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