a$.$ Give a diagram that clearly articulates the three levels of data abstraction in a database, one of them being the view level $(4$ marks$).$ Hint: be sure to not just have one encompassing box for the view level.

b$.$ Define logical semi$-$data independence $(1$ mark$)$

c$.$ Give the motivation behind logical semi$-$data independence $-$ why is it needed at the application layer and why is it desirable? $(1$ mark$)$

d$.$ Describe how logical semi$-$data independence can be achieved $(1$ mark$).$ Hint: do not confuse the application layer with the views.

e$.$ Define physical data independence $(1$ mark$)$

f$.$ Give the motivation behind physical data independence $(1$ mark$)$

$3.(\frac{4}{?}$ marks$)$ The advancement to declarative $DML,$ rather than a procedural $DML,$ is an important advancement in the field of databases.

a$.$ Clearly define the term procedural DML $(1$ mark$)$

b$.$ Clearly define the term declarative DML $(1$ mark$).$

Hint: make sure your definitions are explicit and clearly capture the heart of the difference.

c$.$ Describe how SQL$\text{'}$s DML is mostly declarative $(1$ mark$)$

d$.$ Describe how SQL$\text{'}$s DML is partially procedural $(1$ mark$).$ Hint: do not confuse procedural with procedures.

$4.(\frac{?}{8}$ marks$)$ The DDL $($Database Definition Language$)$ can be used to specify constraints:

a$.$ domain constraints