Record by record update with SQL with no matching key.

I don't know if SQL is the best way to go or just a copyfile (or similar)

I have a physical file which contains actual employee data that I would like to update with "fake" data e.g. Names, Addresses, City, State and zip codes that were randomly generated. I used an excel plugin to generate a "fake" list of employees and then I transfered that to a physical file on the i. So now I would like to read through each record in the live data and replace 5 fields of information in it with data from the fake file. Of course the fake file isn't keyed and wouldn't have a matching employee number in any case, so the challenge is to read the live data record by record and replace it, record by record with the 5 fields from the fake file. There are the same number of records in both files.

I could copy the existing live data file and then add an identity column to sequence the records and then add an identity column to the fake data and then use the identity columns to join and update the live file and then copy the file back, *MAP, *DROP but that seems like a lot of work if I could just run a simple update statement reading through records sequentially.
The objective is to take the live data and replace the personally identifiable info with fake data except I have no common key to join them on.

Ideas?

Thanks

Pete