26 Oct 2024

How to Access MySQLi from a Separate Class in PHPYou are encountering an error when attempting to establish a database connection from a separate...

02 Dec 2024

mysqli::mysqli() Error: Connecting via Socket 'MySQL' FailsWhen attempting to establish a connection to a MySQL database using PHP's mysqli class,...

19 Aug 2025

This article aims to resolve the common "Unable to connect to MySQL server" error in PHP applications, especially when using the XAMPP environment, mysqli_connect(): (HY000/2002) connection failure problem. We will explore the core reasons for such errors, such as improper host address configuration, MySQL service status abnormality, file placement location errors, etc., and provide detailed solutions, sample code and professional error handling methods to help developers quickly locate and repair database connection failures and ensure stable operation of applications.

19 Aug 2025

This tutorial aims to solve common MySQL connection errors in PHP applications, especially the "HY000/2002: A connection attempt failed" issue. The article will explore in-depth common reasons for connection failure, such as improper host address configuration, unrunning MySQL service, and incorrect file deployment location. It also provides detailed troubleshooting steps, standardized connection code examples and error handling mechanisms to help developers quickly locate and resolve database connection barriers and ensure stable operation of applications.

31 Jul 2025

When you cannot connect to the MySQL database, you should first check the connection string format and driver version. 1. Check whether the connection string format is correct. Common errors include port number, database name, parameter symbol errors and driver prefix errors. It is recommended to use the generation tool to verify the format and pay attention to escaping special characters; 2. Ensure that the correct JDBC or database driver is used, different drivers are used in different languages. Pay attention to version compatibility, dependency configuration and driver class name changes, and check the log to confirm whether the driver is loading successfully; 3. Check remote access permissions and firewall settings, including MySQL user permissions, bind-address configuration and server firewall rules, and need to open port 3306 and remote access permissions; 4. Use a simple test program to quickly verify the connection.

12 Aug 2025

This article discusses the root cause of the "No database selected" error when JDBC connects to MySQL because the autoReconnect property and the connection URL do not specify the database name, resulting in a long-term operation. The working principle of the automatic reconnect mechanism is analyzed in detail, and two solutions are provided: it is recommended to always include the database name in the connection URL, and to utilize the createDatabaseIfNotExist property if needed. It aims to help developers build more stable and reliable database connections.