RE: setting up a foreign key

"MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx> wrote on 12/14/2016
04:45:16 PM:

"MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx> wrote on 12/14/2016
04:13:17 PM:

using the index that I created and the Parent description is the
group table and the foreign key is the customer table. It looks
write but, I did it backwards to what you said to do.

There are two major uses of foreign keys -- to tie details with

a

header and to provide a description lookup for some key value. To tie
details with a header you place the foreign key in the detail table
pointing to the header table id column. To provide a description lookup

you place the foreign key in the "master" table pointing to the
description table id column.

I should have mentioned that both of those relationships are a
one-to-many (or many-to-one) relationship. A third major use of foreign
keys is for many-to-many relationships and usually involves a separate
relationship table that (in addition to a primary id column) just has two
(or more) foreign key columns in it to relate two (or more) master tables
to each other.

Sincerely,

Dave Clark