14. Referential integrity
Every foreign key value has a matching value in the corresponding primary key. Referential integrity uses these to ensure that there are no orphan records i.e. it prevents you from deleting related records.
Referential integrity can also alert you if you try to delete a record which is related to another one.
It can also be used to cascade changes made to the database.
challenge see if you can find out one extra fact on this topic that we haven't already told you
Click on this link: Referential Integrity
Attributes and Entities will be covered in the next section