Databases · Middle · Question 75 of 75

What does a foreign key with `ON DELETE RESTRICT` (or the default `NO ACTION`) do when you delete a referenced row?

1The referencing rows are deleted too
2The reference is set to NULL
✓Correct answer: The delete fails while other rows still reference it

Explanation

It protects against orphaned rows. NO ACTION can be deferred to the end of the transaction with DEFERRABLE, RESTRICT cannot.

Further reading

PostgreSQL: Constraints ↗

Test yourself

Take the Databases · Middle quiz: questions and options are shuffled, and you get a review of your mistakes at the end.