Question

Draw an EER diagram for school gyms using standard Chen's notation and following requirement

Each fitness CENTER is identified by a CenterID, a name (e.g. XX Building) and campus. Every CENTER has one or more ROOMS that can be booked for sessions (either group or personal training). As in last time, rooms are noted by their maximum capacity. Within each center, the room number will be unique -- though this time, recognize that Room 116, for example, could exist in more than one center (Is this a strong or weak entity type?).

MEMBERS can sign up for personal or group sessions in different centers (but it is possible they won't sign up for any sessions). Each member has a member ID number.

Each SESSION (PERSONAL or GROUP) requires exactly 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. Sessions are identified by SessionID. 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.

For a session, the start time and room number will be recorded. For group sessions, the type should be recorded (i.e., aerobics, weight training, yoga, etc.). Sessions can start at the same time on the same day but in a different room of a center or in a different center. At a given start hour of a given day, at most one individual or group session may start in a given room of a given center.

Answer 1

An EER diagram for school gyms using standard Chen's notation

The Chen ER Diagram is a famous standard and is broadly utilized worldwide in database and programming plan. The element relationship model proposed by Dr. Chen is developed utilizing a characteristic perspective on how this present reality involves substances and the connections that exist with these distinguished elements. It was intended to use the upsides of the three element information models (network model, relationship model, entity model).

Chen's ERD notation is more explained way to represent entities and relationships in ER diagram.

Rooms entity is weak entity type as a Weak entity is one that can possibly exist when possessed by another. For instance: a ROOM can just exist in a BUILDING. Then again, a TIRE may be considered as a Strong entity since it likewise can exist without being connected to a CAR.

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