The Is Married To relationship in Figure 2-12a would seem to have an obvious answer in Problem and Exercise 2-33d—that is, until time plays a role in modeling data. Draw a data model for the PERSON entity type and the Is Married To relationship for each of the following variations by showing the appropriate cardinalities and including, if necessary, any attributes:

a. All we need to know is who a person is currently married to, if anyone. (This is likely what you represented in your answer to Problem and Exercise 2-33d.)

b. We need to know who a person has ever been married to, if anyone.

c. We need to know who a person has ever been married to, if anyone, as well as the date of their marriage and the date, if any, of the dissolution of their marriage.

d. The same situation as in c, but now assume (which you likely did not do in c) that the same two people can remarry each other after a dissolution of a prior marriage to each other.

e. In history, and even in some cultures today, there may be no legal restriction on the number of people to whom one can be currently married. Does your answer to part c of this Problem and Exercise handle this situation or must you make some changes (if so, draw a new ERD).