In: Computer Science
Draw the ERD in Chen notation corresponding to the following spec:
ERD in Chen notation
As per the given requirement and provided details, the Entities of Boat Reservation ERD are:
1. Sailors:-
Attributes of Sailors Entity: sid, name, age and rating
Primary key of Sailors Entity is 'sid', as the entity is identified by the attribute 'sid'.
2. Boats:-
Attributes of Boats Entity: bid, name and color
Primary key of Boats Entity is 'bid', as the entity is identified by the attribute 'bid'.
3. Reservation:- This entity is an entity formed by boats and sailors to make reservation. So it is to be considered as a Weak Entity.
Primary key of Reservation entity is named as 'reserveid' which is formed by bid of Boats and sid of Sailors(So bid and sid will be the foreign keys for this Entity).
ERD for Boat Reservation by Sailors
This ERD is created as per Chen notation. As the Reservation entity is a weak entity it is represented by double rectangle and the discriminator 'reserveid' underlined with a dashed line.