PHP mysqli_connect() function usage and examples

PHP MySQLi Reference Manual

The mysqli_connect() function opens a new connection to the MySQL server.

Definition and usage

mysqli_connect()The function establishes a connection to the MySQL server and returns the connection as an object.

Syntax

mysqli_connect([$host, $username, $passwd, $dname, $port, $socket])

Parameter

Return value

If a connection to the MySQL server has been successfully established, the PHP mysqli_connect() function returns a connection object. If the connection fails, this function returns a boolean value.false.

PHP Version

This function was originally introduced in PHP version5introduced in and can be used in all higher versions.

Online Example

The following examples demonstratemysqli_connect()Usage of the function (procedural style):

<?php
　　　$host = "localhost";
　　　$username = "root";
　　　$passwd = "password";
　　　$dbname = "mydb";
　　　//Establish Connection
　　　$con = mysqli_connect($host, $username, $passwd, $dbname);
　　　if ($con) {
　　　　　　print("Connection established successfully");
　　　} else {
　　　　　　print("Connection failed ");
　　　}
?>

Output Result

Connection established successfully

Online Example

In an object-oriented style, you can useNew mysqli()The connection is created by the constructor, as shown below:

<?php
　　　$host = "localhost";
　　　$username = "root";
　　　$passwd = "password";
　　　$dbname = "mydb";
　　　//Establish Connection
　　　$con = new mysqli($host, $username, $passwd, $dbname);
　　　if ($con-> connect_errno) {
　　　　　　print("Connection failed");
　　　} else {
　　　　　　print("Connection established successfully");
　　　}
　　　//Close Connection
　　　$con　-> close();
?>

Output Result

Connection established successfully

Online Example

You can also call this function without passing any parameters, as shown below:

<?php
　　　//Establish Connection
　　　$con = @mysqli_connect();
　　　if ($con) {
　　　　　　print("Connection established successfully");
　　　} else {
　　　　　　print("Connection failed ");
　　　}
?>

Output Result

Connection Failed

Online Example

<?php
　　　$connection_mysql = @mysqli_connect("localhost", "root", "wrong_password", "mydb");
　　　
　　　if (mysqli_connect_errno($connection_mysql)){
　　　　　　echo("Failed to connect to MySQL: ").mysqli_connect_error();
	　　exit();
　　　}　　　
　　　echo("Connection established successfully");　　　　
　　　mysqli_close($connection_mysql);
?>

Output Result

Failed to connect to MySQL: Access denied for user 'root'@'localhost' (using password: YES)

PHP MySQLi Reference Manual