Getting started with PHP database operations: How to use the mysqli_connect function to connect to a MySQL database

Getting started with PHP database operations: How to use the mysqli_connect function to connect to a MySQL database

Introduction:
In Web development, database operations are a very important part. Databases can store and manage large amounts of data, providing data persistence and security. PHP is a scripting language widely used in web development and provides many interfaces and functions for database operations. This article will introduce how to use PHP's mysqli_connect function to connect to a MySQL database and give some code examples.

1. Preparation:
Before starting to use the mysqli_connect function, we need to confirm the following points:

1. You have correctly installed and configured the PHP environment.
2. You have installed the MySQL database and know the host name, user name, password and other information of the MySQL database.

2. Connect to MySQL database:
In PHP, we can use the mysqli_connect function to connect to the MySQL database. The basic syntax of this function is as follows:

mysqli_connect(host, username, password);

host: Specify the host name of the MySQL server, which can be an IP address or domain name.
username: User name for logging in to the MySQL database.
password: Password to log in to the MySQL database.

The following is a practical example, assuming that the host name of the MySQL database is localhost, the user name is root, and the password is empty:

$host = "localhost";
$username = "root";
$password = "";

// 连接 MySQL 数据库
$conn = mysqli_connect($host, $username, $password);

// 判断连接是否成功
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

echo "连接成功";

In the above example, we first define the MySQL server hostname, username and password. Then use the mysqli_connect function to connect and assign the returned connection object to the variable $conn. Finally, we use the mysqli_connect_error function to determine whether the connection is successful. If an error occurs, an error message will be printed and the connection will fail. If the connection is successful, "Connection successful" will be output.

3. Close the database connection:
After using the database, you should close the connection with the database to release resources. You can use the mysqli_close function to close the database connection. The following is an example:

mysqli_close($conn);

4. Summary:
This article introduces how to use PHP's mysqli_connect function to connect to a MySQL database, and gives corresponding code examples. Connecting to the MySQL database is the basic step for database operations. Mastering this foundation will lay a good foundation for subsequent database operations. I hope this article can help you get started with PHP database operations.

The above is an introduction to getting started with PHP database operations. I hope it will be helpful to you.

Reference materials:

• PHP official documentation: https://www.php.net/manual/en/mysqli.connect.php

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