Usually when an abritrary ID is used in place of actual codes it is necessary to provide alternative keys to assure uniqueness of the values. The patterns here do not show any alternative keys so I can only assume there are none. Most designers forget that is you have (code, description) The code is the primary and the description must be an alternate key to prevent duplicate descriptions. Now add in a new value such as (ID, code, Description) Now the primary key is probably ID + Code - but remember you must also have ID + Description to prevent the duplication. With each additional component to the pattern the issue of maintinaing unique codes and descriptions become more difficult. A real world example. The city was concerned that not enough tax revenue was created by a certain property type. Upon a one-minute investigation it was found that 5 codes had the same description. So, if you did not ask for all 5 codes you would not get the right answers. SOlution - assign one code + description then update all the bad records to that one code-description and what do you know - revenue. Without assurance that this holds true in this design I hold a reserved opinion. (No duplicates of any columns in lookup tables)

Pat