Help with this assignment for database systems course :

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

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.