Consider the CD cover in Figure 5-61.
A. Specify identifiers and attributes for the entities CD, ARTIST, ROLE, and SONG.
B. Construct a crow's foot model showing relationships among these four entities.
Name each relationship and specify cardinalities. Indicate which cardinalities you can justify on the basis of the CD cover and which you will need to check out with the users.
C. Consider a CD that does not involve a musical, so there is no need for ROLE. However, the entity SONG_WRITER is needed. Create a crow's foot model for CD, ARTIST, SONG, and SONG_WRITER. Assume that an ARTIST can either be a group or an individual. Assume that some artists record individually and as part of a group.
D. Combine the models you developed in your answers to B and C. Create new entities if necessary, but strive to keep your model as simple as possible. Specify identifiers and attributes of new entities, name new relationships, and indicate their cardinalities.