Entity Relationship Diagram

MSIS 3333

Draw the entities and relationships suggested by each word problem. Include the proper foreign key(s). Remember to make a copy for yourself.

Unary Relationships

1. We run one of the nicest German Shepherd breeding facilities in the southwest region. Each dog has a name that is unique, a basic color and a disposition. We want to keep track of only the most recent breeding mate for any given dog, when they bred, and the litter size. All of our dogs are currently part of a breeding pair.

2. Same as #1, but our dogs often breed repeatedly with the same dog and we don’t want to lose any data over time.

3. Employees (Empid, name) can mentor other employees, or not. Every employee has a single mentor. Mentors only have one person that they mentor at a time (a mentee). When they get a new mentee we just overwrite the record of the previous mentee.

4. Same as #3 but we do want to keep the historical record of all mentor / mentee relationships, as well as the start and end date of each.