Find and change automatically a field

[ablarer]

I am a newbie and have some problems.

I want to check, after I added a new record, if in all already existing records two fields a) "Product" *and* : "Seller" contain the same values as in the newly generated record in "Product *and* "Seller". If that is so I want that the field "version" in the new record goes up one number compared to the higest existing number of "version" in a already existing record with the same values in "Product" *and* : "Seller". Product, Seller and Version are number fields. E.g. Existing records:

Record 1: Product = 1, Seller = 3, Version 1;

Record 2: Product = 1, Seller = 4, Version 1;

Record 3: Product = 1, Seller = 3, Version 2.

New record.

Record 4: Product = 1, Seller = 4, Version becomes automaticaly 2 because Product and seller is the same as in record 2.

I hope it's clear want I want. Please could anyone help me?

[aaa]

You must create new calc field Product_Seller=Product&"_"&Seller

Then to build self relation on this field, let it be A

Then in auto enter option for Version field you must specify calculation :

"Version "&Count(A::Version)