Data modeling problems...

[Kris]

I'm working on an app in VB6, I've written alot of the core components and
understand the business problem, but I'm having trouble designing my database
to effectively model how things need to work.

Here is the sum of the issue: The system needs to generate proposals for
work to be performed at a property, usually these proposals can be submitted
to a Realtor, but occasionally they are done for an Owner only, in the case
where no Realtor is involved. I'm having trouble modeling my Proposal table
to allow for this. I've played around with a Contact table, and have the
Proposal refer to a Contact, which refers to a Realtor OR an Owner. Can
someone suggest the best way to do this in regards to the ER design?

Thanks,

Kris

[VBGuy]

Try using a junction table which holds common key fields. Allow nulls in
the foreign key fields relating to Relators and Owners (use Inner Joins or
Left Outer Joins) so that it can refer to one or both and then contain the
rest of the attributes for each particular proposal. If I understand your
question, it shouldn't be too hard to model this solution..

"Kris" <krs_goss@yahoo.com> wrote:
>
>I'm working on an app in VB6, I've written alot of the core components and
>understand the business problem, but I'm having trouble designing my database
>to effectively model how things need to work.
>
>Here is the sum of the issue: The system needs to generate proposals for
>work to be performed at a property, usually these proposals can be submitted
>to a Realtor, but occasionally they are done for an Owner only, in the case
>where no Realtor is involved. I'm having trouble modeling my Proposal table
>to allow for this. I've played around with a Contact table, and have the
>Proposal refer to a Contact, which refers to a Realtor OR an Owner. Can
>someone suggest the best way to do this in regards to the ER design?
>
>Thanks,
>
>Kris