Hi Steve,

The real world problem is exactly as I've outlined it. I'm modelling Apartment and Landlord data the way I've described.

I think you and Jason may be right in...

I guess in addition to the AreaCodeID, I can add a CityCodeID to the Apartment table. Then I can constrain Apartment and Area by AreaCodeID and CityCodeID, and Constrain...

K guys,

Since you seemed to enjoy the challenge I wonder if I can impose one last question on you.

An extension of the existing problem domain.

Consider two new tables:

Landlord

Apartment

Landlord has only...

Thanks a lot to Jason and Steve for helping me to understand this concept.

Jason's code does what I was looking for. Steve, your code almost does. I think...

Sorry Steve, still doesn't validate properly.

As a test, you can try this:

Once you create a couple users, cities and areas, go into your User_Areas table and you'll notice that you...

Hi JTS, I'm not sure I fully understand what you're talking about. As described, your scenario would still allow for a User to have 3 areas, each one being...

Hi Steve,

That won't work for a couple reasons.

The first is that you can still end up with User_Areas that belong to a city that is NOT the same city as...

Jason, you may be right, I'm not sure about the way I worded it. Let me just use plain english:

A "User" can belong to many "Areas". An "Area"...

Example:

A User can ONLY be in New York City.

Queens, Brooklyn, Manhattan, Long Island and Harlam are all areas, each of which belongs exclusively to "New York City".

A user can have...