Database design

[Anon]

I have a doubt about the best way to solve this:
I have a PAYMENTS table with a RECEIVER field, the problem is that the "receiver" may be in two different tables, EMPLOYEES and SUPPLIERS. How can I create a relationship between this 3 tables?

[Anon]

Create an ENTITIES table and an ENTITY_TYPE table. Then store all entities in the ENTITIES table (i.e. employees, suppliers, etc.) Then in the entities table, create a field for the ENTITIY_TYPE which would be either person, company, or whatever else you think of. I ran into this same bit of confusion a while back while designing a database for a client. I just decided to think about people and companies the way the IRS does. That's how I came up with Entities and Entity Types. It groups everyone together nicely and allows you to use any entity you want. Hopefully that helps.

If you have specific info about employees, leave it in that table and just link the entities that are employees to the employee table. But use their ENTITY_ID. You would do the same thing to suppliers.

AaronZoller
www.AaronZoller.com

[Anon]

Thanks for your help Aaron.
I thought about this solution, but how to make a query linking all tables with different identities types?
Actually I'm using a UNION to add the queries of all entities types. Is this the best way to do it?