The Area being Modelled is :-
An Elephant Sanctuary

A.1 This is a Statement of the User Requirements.





Question: I was wondering if you could pleasee help me.
a little bit of advice for a ERD that i have to produce.
just a little background.
i have to design a ERD for an elephant sanctuary and i am
just having trouble getting my head round the relationships between
employee, volunteer adn managers with the sanctuary.

So far i have the following: http://img.photobucket.com/albums/v635/monkey_mafia66/erd.jpg
i know that volunteer needs to be a subclass of employee because it
shares the same attributes as employee as they are given a temporary
employee id just wasnt sure whether to do a disjointed sublcass with manager.

does this look okay?

it states that there are pre definied arrival dates and the system needs to
record which date the volunteers are arrive and when they leave from the sanctuary.

how would i present this? the volunteers also share a bungalow and the system needs
to record which room has beeen allocated. would i create a weak entity called bungalow?



B. The Things of Interest, ('THINGS'), include :-
B.1 Elephants
B.2 Employees
B.3 Volunteers
B.4 Others to be determined

D. Other Characteristics of these THINGS include :-
D.1 To be determined

E. Sample Data includes :-
E.1 To be determined

F. Typical Enquiries include :-
F.1 To be determined