- A standard method that enforces RI on a row-by-row basis
- A batch method that enforces RI on a statement basis
Both methods offer the same measure of integrity enforcement, but perform it in different ways.
A third form, sometimes informally referred to as soft RI, is related to these because it provides a declarative definition for a referential relationship, but it does not enforce that relationship. Enforcement of the declared referential relationship is left to the user by any appropriate method.