a) Create an ER diagram using standard Chen notation for the following scenario:

A friend who works for Penn State Campus Recreation told you they would like to set up a database to keep track of the group fitness rooms and the classes in the IM Building. This database will only serve the IM building. Each ROOM has a unique number (e.g., 001, 002, 003, 116, etc.). They also want to keep track of the maximum capacity of each room.

MEMBERS can sign up for group fitness SESSIONS (but it is possible they won't sign up for any sessions). For each group SESSION, the date and start time, and room number will be recorded.

Each group session is officially led by one TRAINER. Even if there is another person co-teaching the class, the database will only store one official trainer of record for each class session. A trainer is identified by his/her certification number. The system should accommodate trainers who are interns and may not have led any sessions yet.

b) An ER diagram cannot easily support description/enforcement of temporal constraints. What would be an example of a temporal constraint in this diagram?