Entity-Relationship Diagrams

[cw42]

For this relationship...

[Employee]-O-----<1:N>------O-[Computer]

If it was flipped around, would I change the middle part to N:1, Or leave it as 1:N?

[Computer]-O-----<N:1>------O-[Employee]

 

[cw42]

anyone?

 

[hjo3]

I dunno what you're talking about, but I bet you're in the wrong forum.

 

[brtspears2]

Lets break it down. An employee can use many computers. But can a computer have many employees. Sure!

I would leave it 1:N, but then I got a C- in database design class.

 

[Platypus]

This is a many to many relationship so each side should be the same I think.. it's been a while.

 

[cw42]

Question: Why is the process of data modeling interative?

 

[gsethi]

i think you would flip it to N:1.
Employee -> Computer is one-to-many relation. (one employee can use many computers)
(many to many would be N:N).

N:N relation would seem more realistic for that relation though.
Exact answer would depend on other constraints and requirements by the design. (Almost an year since I took DB classes...if you want an exact answer, i can revise my notes tomm and let you know).

But why would you want to reverse that relation when you are doing an E-R diagram for a project ? Maybe list more project guidelines (or was this your only question ?)

 

[gsethi]

Originally posted by: cw42
Question: Why is the process of data modeling interative?

ok, you should do your own hw now Read the book and you will find the answers in there

for my DB class, (for me) book and lecture notes (were available online by prof ) were more helpful than in-class lectures.