hi could anybody please offer 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/v6...afia66/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?