What to do when mysqli::connect fails to connect to the database? Learn how to catch and handle error messages

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<p><h1>What to do when mysqli::</span>connect fails to connect to the database? Learn how to catch and handle error messages</h1></p>
<p><p>When connecting to a MySQL database using PHP, the error messages output by <code>mysqli::connect<span>

can help us determine whether it's a configuration issue or a server anomaly.

3. Enable Exception Mode for Elegant Error Handling

Starting from PHP 5.5, mysqli supports handling errors as exceptions. You can enable this as follows:

mysqli_report</span>(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

try {
    $mysqli = new mysqli("localhost", "username", "password", "database");
    $mysqli->set_charset("utf8mb4");
} catch (mysqli_sql_exception $e) {
    error_log("Database connection failed: " . $e->getMessage());
    echo "Sorry, the database is temporarily unavailable. Please try again later.";
}

This method not only allows for graceful error capture but also prevents exposing sensitive information in production environments.

4. Recommended Error Handling Strategies

• Development environment: You can print detailed error messages for debugging purposes.
• Production environment: Only display user-friendly messages, and write detailed error information to logs.
• Log recording: Use error_log() or a custom logging class to record exceptions.
• Unified database connection wrapper: Write it as a function or class for reuse and centralized error handling.

5. Conclusion

Database connection failures are a common issue in PHP development. By using the error properties or exception handling mechanisms provided by mysqli, we can efficiently capture and pinpoint errors. It is recommended to adopt good habits such as encapsulating the connection and recording logs in actual development. This not only improves code quality but also reduces the difficulty of troubleshooting in production environments.

The next time you encounter a “connection failed” message, consider reviewing the methods in this article. You may quickly identify the issue and resolve it.