> You could use something similar to what is in Codebook. In the "Default Value" of a table field, call a function that generates the key. Make the key an integer value that can have a start/end range. Each call to this function increments the value (base 10, or base 62 or something like that) by one (the "current" value would have to be stored in a table). Set-up each station with a different range. Then when you merge these data sets you'll know all the keys are unique. You also have the added benefit of knowing where the information was generated (based on the range of the unique key).

I've tried both methods during 15 years of programming, and found the 'prefix' method is easier to handle. Like the range it allows you to see where the data was first input, but it never has to be updated if one site fills up its quota of ID codes.

My $.02 US
Barbara