Duplicates Problem in Concatenated fields

[DblDogDare]

I have a table with two fields ECP and Rev. Duplicates are OK in each field, but not when concatanated. Is there any way to "No Duplicates" on combined fields in a table? I have queries , forms, etc., that concatanate these, but I am finding that my users are duplicating. Any help is greatly appreciated.

 

[DblDogDare]

Problem Solved

I figured it out. I found the fix an another forum. I created an index on the 2 fields.