Hi,
I’ve three questions, would someone answer them please,
I have 3 entities:
The book entity(BookNo,BookNmae,AuthorName,Price...etc), the MembershipCard entity(CardNo,MembershipNo,ClientNo,PublishDate,Em pNo..etc), and the Client entity(ClientNo,ClientName,ClientAddr,ClientPhoneB ookNo,RequiredBookNo,..etc)
1-What is the relationship degree between them, is it ternary or binary?and Why?I'm so confused ,my answer is ternary, I made a (1:m) relationship between the clients entity and the books entity (a client may buy more than one book), (1:m) relationship between the employee entity and the books entity (an employee may sell more than one book)and a (1:m) relationship between the employee and the Client(an employee may serve more than one client(is it right or it's (M:N)).
So is my answer is right or wrong, please help me to understand, I’m so confused.
2- Is the cardinality degree between the Client entity and the book entity , (0,N) for the client entity and (1:N) for the book entity??
3-What is the best model to use in designing data in general,Chen's model or Crow's Foot and why?I think it's Crow's one ,for it's more arranged and easy to read.
with thanks
deema(bright_moon)