What occurs when a delete rule is set to CASCADE in database relations?

When a delete rule is set to CASCADE in database relations, it means that if a record on the "one" side of a relationship is deleted, all corresponding matching records on the "many" side will also be automatically deleted. This behavior helps to maintain referential integrity within the database by ensuring that there are no orphaned records left in the "many" side of the relationship.

For example, consider a database scenario with two tables: one for "Authors" and the other for "Books." If an author is deleted from the "Authors" table and a CASCADE delete rule is applied, all books associated with that author in the "Books" table will also be deleted. This automatic deletion prevents the situation where a book record would exist without an associated author, thus ensuring that the data remains consistent and valid.