$(2)$ Consider two E$-$R models. Model A consists of two entities and one relationship joining them. The entities are

LECTURER and COURSE and the relationship is TEACHES. The second model consists of three entities; the first and

the third are the same as above but the second entity is called LECTURE. The first and second entities are joined by a

relationship called GIVES while the second and the third entities are joined by a relationship called $OF.$

a$)$ Draw the E$/$R diagrams for both models.

Model A

Model B

b$)$ Which of the following statements are correct? Briefly justify your answers to all statements. You will not receive

marks for answers without explanation.

i$.$ Both models allow a course to have more than one lecture from the same lecturer.

ii$.$ Model B is more appropriate if information about all lectures, past and present, is to be stored.

iii. Model A does not allow lecture date and time to be stored.

iv$.$ Model B leads to more tables than Model A does when translated to the relational model.