Four tables

[liiza]

I have four tables CC....FA1.... FA2.... WBS (those do mean names in my
world)... CC can go with any of the other three as FA1 can go with any of the
other 3 these can be in any combinations, by itself, combined with one other
combined with 3 others. And each table has a different # of Entries that can
combine with the others. Do i need junction tables for each and every
combination? Thank You!

 

[Pete D.]

You need a junction table if each record in the table has multi records in
the other table and each record in the other table has many records in
table.

For instance
Many different trucks are all the same make/model
Many repair books apply to the many trucks that are same make/model.
This will require a junction table or many to many.

 

[liiza]

because many of CC can go with Many of FA1 and vice versa...as can all the
others i'd need a junction table.... but do i need one for each combination?
such as FA1 and FA2

Example: CC=Trucks FA1= Manuals FA2 = Parts
Many parts can be in many of the manuals and used on many trucks
Many trucks have the same manuals and the same parts

thank you so much for your help

 

[Pete D.]

You answered your question, very logically I might add. Now you can have
other relationships also. Don't get stuck on the one. If you relate many
manual to many trucks and many parts to the many manuals this will cascade
to the trucks. Of course this will require the manuals to be related to the
trucks. You can also relate them directly depends on you situation and what
works for you. Are you primaraly dealing with the truck record or do you
sell repair manuals. You usually look from top of the pile to bottom. I
sell trucks and it is the primary table, everything cascades from that.

 

[liiza]

ohhh that makes more sense! Sorry I'm struggling with having to come up to
speed and develop a database at the same time, been a long time since I've
even used it....I'm thinking if i make one junction table and put CC,
FA1,FA2, and WBS keys in it then it will be right!

thank you so very very much

 

[Pete D.]

Ummmm, no each item is one enity and must be related as such. Those items
can pass through another table if they relate.

 

[liiza]

i should have said i'd put the key from each table into another table gad i
feel like i'm an idiot... sorry for being so dense

 

[Pete D.]

Nope, sorry I din't understand your response but you seem to have a handle
on it. Post back if you get stuck while building.