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.