The Is Married To relationship in Figure 2-12a would seem  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.
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 that the same two people can remarry each other after a dissolution of a prior marriage to each other.

Transcribed Image Text:

(a) Unary relationships Manages Stands After Is Married To TEAM PERSON EMPLOYEE One-to-one One-to-one One-to-many