Question

Hi I need be able to link related applications and am trying to work out the best practice table structure for saving, updating and deleting.

I have the following table:

APPLICATION{ApplicationId, Name, Description}

I need to be able to say Application 1 is linked to 2 and 3. Therefore if you open application 2 you’d see that it is linked to application 1 and 3. Then application 3 is linked to 1 and 2.

What is the best table structure for a linked table?

EDIT

My main query is will I need a record for each join ie for applications 1, 2 and 3 would I need 6 records? 1->2, 1->3, 2->1, 2->3, 3->1, 3->2 ?? If not what is the best query to return all linked apps for a given id?

Answer 1

application_association
-------------------------
application_1_id
application_2_id
relationship_type
begin_dt
end_dt

use relationship_type to specify how the applications are related, and use the dates to specify when that relationship was valid

edit:

maybe there is a collective misinterpretation of your use of the word ‘linked’.

If you instead mean ‘grouped’ then you might consider a structure like the following:

group
------------------
group_id
name

application_group
-------------------
application_id
group_id

here you can just place applications into the same ‘group’ and then query them all back when they are in the same group.