When Should You Manually Check for mysqli_connect() Errors?

When Should We Manually Check for Connection Errors in mysqli_connect()?

The PHP manual for mysqli_connect() advises checking the return value and displaying error messages on the screen. However, it remains questionable if manual error checking is necessary.

Benefits of Automatic Error Display

MySQLi automatically generates warnings in the event of failed connections. These warnings provide sufficient information, including error code, message, and line number. Manual checking does not offer additional insights.

Drawbacks of Manual Error Checking

• Redundancy: Displays errors twice, once as a warning and again in the manual check.
• Limited Information: Manual checking does not provide more information than the warning.

Configuration for Error Handling

If warnings are not visible, check the PHP error log file. Phpinfo() can help locate this file. Ensure that PHP settings are configured as follows:

Production:

• error_reporting: E_ALL
• log_errors: On
• display_errors: Off

Development:

• error_reporting: E_ALL
• log_errors: On
• display_errors: On

Exceptions over die/exit

Avoid using die/exit. If the mysqli connection fails, throw an exception to halt script execution. Configure mysqli to automatically throw exceptions:

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'my_db');

Limitations of mysqli_error()

Neither $conn->error nor mysqli_error($conn) can display connection-related problems. They require a valid mysqli connection.

Conclusion

Manual error checking for mysqli_connect() is unnecessary. MySQLi's automatic warnings provide sufficient information. In production environments, configure PHP to log errors for security reasons. In development environments, enable error display for debugging. For comprehensive error handling, throw and handle exceptions.

The above is the detailed content of When Should You Manually Check for mysqli_connect() Errors?. For more information, please follow other related articles on the PHP Chinese website!