RAISE for notices and exceptions in PostgreSQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the RAISE statement do in PostgreSQL?

The RAISE statement sends messages or errors during the execution of a PL/pgSQL block. It can show notices, warnings, or raise exceptions to stop execution.

beginner

What are the different levels you can use with RAISE in PostgreSQL?

You can use RAISE with levels: NOTICE, WARNING, EXCEPTION, LOG, and DEBUG. EXCEPTION stops execution, others just show messages.

beginner

How do you raise a custom exception with a message in PostgreSQL?

Use: RAISE EXCEPTION 'Your message here'; This stops the function and shows the error message.

beginner

What is the purpose of RAISE NOTICE in a PL/pgSQL function?

RAISE NOTICE shows an informational message to the user without stopping the function. It's useful for debugging or status updates.

intermediate

Can you include variables in RAISE messages? How?

Yes, use format strings with % placeholders and provide variables after the message. Example: RAISE NOTICE 'Value is %', my_var;

Which RAISE level in PostgreSQL stops the execution of a function?

A NOTICE

B WARNING

C EXCEPTION

D LOG

RAISE EXCEPTION stops the function execution and raises an error.

What does RAISE NOTICE do in a PL/pgSQL block?

A Stops execution with an error

B Shows an informational message without stopping

C Logs a message to the server log only

D Ignores the message completely

RAISE NOTICE displays a message to the client but does not stop execution.

How do you include a variable value in a RAISE message?

A Use % placeholders and pass variables after the message

B Use $variable directly inside the string

C Concatenate strings with +

D Variables cannot be included in RAISE messages

RAISE supports format strings with % placeholders and variables passed after the message.

Which RAISE level is best for debugging messages that you want to see only sometimes?

A EXCEPTION

B NOTICE

C WARNING

D DEBUG

RAISE DEBUG is used for detailed debugging messages, which can be enabled or disabled.

What happens if you use RAISE WARNING in a function?

A A warning message is shown but function continues

B Function stops immediately

C Message is logged but not shown to user

D Nothing happens

RAISE WARNING shows a warning message but does not stop the function execution.

Explain how to use the RAISE statement to show a notice and to raise an exception in PostgreSQL.

Think about messages that inform vs. errors that stop.

Describe how to include variable values inside RAISE messages in PL/pgSQL.

It's similar to formatting strings in many programming languages.