3.) Create an ER diagram that represents this situation. Movies show actors in roles. The role has a name. Each role in the movie relates to other roles as rivals. An example of rivals would be teams in the movie Glee where the role is best glee group. There are possibly many rivals for each role. There is also one particular role that relates to another role as a nemesis. An example of a nemesis is batman versus the jester where the role is dominant person in Gotham. Each role has only one nemesis. Show key(s). 4.) Construct an ER diagram representing the following situation. A "beer at a bar" is repesented as a combination of a particular bar having and name and address and a particular beer having a name and manufacturer. What is the key for "beer at a bar"? 5.) Construct an ER diagram representing the following situation: A sales-related company has StaffPersons. There are different kinds of staff, Salespersons, Administrative Assistants, and Managers. Only Managers get bonuses, only Admistrative Assistants are tested for word processing skill level, and only salespersons have a sales area and a car allowance. All staff have a name and SSN. The company has Branches, and a Manager manages only one Branch and a Branch has only one Manager. Staff all work in a particular branch.