Beginner's Guide: Step-by-Step Setting Up a PHP Database Connection

PHP database connection is completed in four steps: obtaining credentials, importing the MySQLi extension, creating the connection object, and closing the connection. For MySQL database, the connection example is as follows: require_once("mysqli.class.php"); $mysqli = new mysqli("localhost", "root", "password", "employees");

Beginner's Guide: Step by Step Establishing a PHP Database Connection

Establishing a database connection is an essential part of PHP development. This guide will walk you through setting up a PHP database connection step by step and provide a practical case for you to practice.

Step 1: Obtain database credentials

Obtain the following credentials from the database server administrator or service provider:

• Database host name Or IP address
• Database name
• Database user name
• Database password

Step 2: Import the mysqli library

At the top of the script, import the MySQLi extension:

<?php
require_once("mysqli.class.php"); // MySQLi 扩展的路径
?>

Step 3: Create the connection object

Use mysqli::__construct() Function creates a MySQLi connection object:

<?php
$mysqli = new mysqli("主机名或 IP", "用户名", "密码", "数据库名");
?>

Practical case: Connect to MySQL database

Assume we want to connect to a MySQL database named "employees", The host name is "localhost", the user name is "root", and the password is "password", the code is as follows:

<?php
require_once("mysqli.class.php"); // MySQLi 扩展的路径

$mysqli = new mysqli("localhost", "root", "password", "employees");
?>

If the connection is successful, the $mysqli object will contain the database connection.

Verify connection

You can check the $mysqli->connect_errno attribute to confirm whether the connection is successful. If it is 0, the connection is successful:

<?php
if ($mysqli->connect_errno) {
    echo "连接失败: " . $mysqli->connect_error;
} else {
    echo "连接成功";
}
?>

Close the connection

Use the mysqli_close() function to close the connection and release resources:

<?php
$mysqli->close();
?>

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