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. 😉