Question

Consider the following diagram:

b2

What are the minimum and maximum number of Cs that can be associated with any one A? This is the same as asking “What are the existence and cardinality for the C to A relationship?”

Substitute A:person and B:manage and C:project in the above ER diagram. Suppose that someone told you that the following three facts are true. Are these consistent with the diagram? Answer yes or no for each of the three facts. If your answer is no, then explain why it is inconsistent.

Mackenzie manages the Town project.

Lindsey manages the City and International projects.

Joe doesn't manage any projects.

Answer 1

minimum and maximum number of Cs that can be associated with any one A

minimum number of Cs ----- 1

maximum number of Cs ----- many

A:person can B:manage one or many C:project

Mackenzie manages the Town project. ------consistent , a person manages one project

Lindsey manages the City and International projects. ------ consistent, a person manages many projects

Joe doesn't manage any projects. -------- inconsistent as person manages at least one project as per diagram