A little background:

I work for a real estate company. Sometimes a large piece of property is composed of several smaller sales, or sometimes it's already one big chunk.

I'm trying to create a layout that, if the property is comprised of multiple sales, it will total up all the different site sizes and prices, and place that number into a field (say, Total Price and Total Size).

If that calculation is greater than 0 (i.e., multiple sales have been entered) then I want to use that number for fields called Price and Size. However, if no data has been entered there, then the site would be one big chunk, and I'd like to be able to hard key the fields Price and Size.

Is there a way to set up a statement that is something like If Total Price>0, then Price=Total Price, Else allow user entry?

I hope this isn't too obtuse.

I would create 1 table for inital sales, and 1 table for Final Values or something like this.

Relate them with a Property_ID. The idea here, is that each of your "Small sales." would all have the same property ID.

You could then get the totals using the relation, and this would make it so if there was only one sale, you got that number, wheras if there were multiple ones, you got the total. Same in Size.

Then, when you input a sale, you input it the same way weather it is a small sale or a big chunk.

Thats what I would try doing first. I'm sure someone else here can think of an easier, more efficent way to do it.

Thanks for your suggestion Zero. I've mocked up your suggestion, and it seems that it would get the job done. My only hesitation with it is that it makes data entry a bit more cumbersome as you have to switch to an alternate layout to enter the various "small" sales.

In a similar database, I had tried this solution: I had the Price field set up to always be Total Price, and just entered the sale information for a "chunk" sale as the only entry in the Multiple Sale format. I have one layout that shows the Multiple Sale breakdown and one that does not. For the layout that does not show multiple sales (where I would normally just be entering the total price directly), I created non-printing fields off to the side that I can hard key the information so that it's stored as the one and only "small chunk" of the property.

I'm not sure I'm explaining myself very well here, and I'm not sure which route works best for me. I like the portal idea, because then I don't have to create fields like SalePrice1, SalePrice2, SalePrice3 for each possible small chunk sale. I'm leaning more toward that avenue. But again, for ease of use, I'd like to not have to switch to another layout to enter my small sales.