Error handling with PDO exceptions in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is PDO in PHP?

PDO stands for PHP Data Objects. It is a way to connect to databases in PHP using a consistent interface.

beginner

Why use exceptions for error handling with PDO?

Exceptions let you catch errors cleanly and handle them without stopping the whole program abruptly.

intermediate

How do you enable exceptions for PDO errors?

Set the PDO attribute PDO::ATTR_ERRMODE to PDO::ERRMODE_EXCEPTION when creating the PDO object.

intermediate

What PHP code snippet shows catching a PDO exception?

try { // PDO code here } catch (PDOException $e) { echo 'Error: ' . $e->getMessage(); }

beginner

What happens if you don't catch a PDO exception?

The script stops running and shows a fatal error message, which is not user-friendly.

How do you tell PDO to throw exceptions on errors?

A Call PDO::enableExceptions() method

B Use try-catch without setting anything

C Set PDO::ATTR_DEFAULT_FETCH_MODE

D Set PDO::ATTR_ERRMODE to PDO::ERRMODE_EXCEPTION

You must set the error mode attribute to PDO::ERRMODE_EXCEPTION to enable exceptions.

What class do you catch to handle PDO exceptions?

A Exception

B PDOException

C ErrorException

D RuntimeException

PDO throws exceptions of the class PDOException.

What is the benefit of using try-catch with PDO exceptions?

A It prevents the script from stopping abruptly on errors

B It makes the code run faster

C It automatically fixes database errors

D It disables error messages

Try-catch lets you handle errors gracefully without stopping the script.

What method gets the error message from a PDO exception?

A getError()

B errorInfo()

C getMessage()

D getCode()

getMessage() returns the error message from the exception.

If PDO error mode is not set to exceptions, what is the default behavior?

A PDO returns false on errors without exceptions

B PDO logs errors automatically

C PDO throws exceptions anyway

D PDO crashes the script

By default, PDO returns false on errors and does not throw exceptions.

Explain how to set up PDO to use exceptions for error handling and why it is useful.

Think about setting attributes when creating PDO and catching exceptions.

Describe what happens when a PDO exception is thrown and not caught in your PHP script.

Consider the impact on the program flow and user experience.