Can you deal with a relation as a non-decomposed m:n in one object and as
a decomposed m:n another? Will you run into problems doing this?
For example, suppose you have a USER table and a ROLE table that are
related by a USER_ROLE table: a simple m:n relationship which I would like
to deal with as a non-decomposed m:n in the USER and ROLE objects, so that
you can simply do user.getRoleCollection() or a role.getUserCollection().
Also suppose there is also an ITEM and LIST table in an m:n relationship
via a ITEM_LIST table. I would like to treated as non-decomposed one, so
that you could have item.getListCollection(), list.getItemCollection()
methods.
There is also an INCLUSION table that relates the USER_ROLE and ITEM_LIST
tables in an m:n relationship (To tell you who in what role, included what
item in which list. And yes, multiple user/roles can include the same
item in a list -- sort of a "list of people who requested this item on
this list").
In the object model, I would like treat that Inclusion relationship as
decomposed. So that I could have a method list.getInclusionCollection()
which would give me all the Inclusions to this list.
USER_ROLE is both involved in an m:n decomposed and m:n non-decomposed
relationship. Will this cause problems?
USER: USER_ROLE: ROLE:
USER_ID(PK) USER_ID(FK:USER) ROLE_ID(PK)
ROLE_ID(FK:ROLE)
ITEM: ITEM_LIST: LIST:
ITEM_ID(PK) ITEM_ID(FK: ITEM) LIST_ID(PK)
LIST_ID(FK: LIST)
INCLUSION:
USER_ID,ROLE_ID(FK: USER_ROLE)
ITEM_ID,LIST_ID(FK: ITEM_LIST)
Thanks in advanced,
yuji
----
Yuji Shinozaki Computer Systems Senior Engineer
[EMAIL PROTECTED] Advanced Technologies Group
(804)924-7171 Information Technology & Communication
http://www.people.virginia.edu/~ys2n University of Virginia
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