Zend Certified PHP Engineer (ZCPE) Practice Test

To check for errors in a database connection in PHP, using the connection object or the `mysqli_connect_errno()` function is the most effective approach. When establishing a database connection using the MySQLi or PDO extension, the connection object provides immediate feedback on whether the connection was successful.

If the connection fails, the `mysqli_connect_errno()` function can be utilized to retrieve the error code associated with the failed connection, while the `mysqli_connect_error()` function can provide a human-readable error message. This method allows a developer to handle the error appropriately, either by logging it, displaying a message to the user, or taking corrective action.

Using just a try-catch block does not inherently provide connection error information unless additional conditions are implemented to check the connection status. Checking the error log file or using the `error_reporting()` function may assist in finding out about general errors but do not directly provide instant feedback or details related to a specific database connection attempt. This makes checking the connection object or utilizing `mysqli_connect_errno()` the most straightforward and effective way to handle errors when connecting to a database.