The DDL $($Database Definition Language$)$ can be used to specify B constraints:a$.$ domain constraints b$.$ referential integrity,sudashans wellest e and serim "Database system Concepts', $*$ etin, $2020,$ Ac$.$ assertions, andd. autho

$(/8$ marks$)$ The DDL $($Database Definition Language$)$ can be used to specify constraints:

a$.$ domain constraints

b$.$ referential integrity,

c$.$ assertions, and

d$.$ authorization

For each of these four constraints a$-$d above give a definition $(1$ mark each$)$ and give an example in the real world where the constraint would be useful $(1$ mark each$).$ Hint: domain constraints have two fundamental aspects, remember to include both in your answer. For referential integrity, do not include in your answer the how $($e$.$g$.,$ mechanics of how it is enforced with PKs and FKs$),$ instead focus on the concept. Lastly, do not mix up assertions with other constraints.