Primary Key Hash help

I have a huge data file with rows like this:

AL Prattville  36066  01001 US  01-001-0870 01 001 1 3 0162328 1
AL Prattville  36067  01001 US  01-001-0870 01 001 1 3 0162328 1
AL Prattville  36068  01001 US  01-001-0870 01 001 1 3 0162328 1

The unique key for each row is all columns. I'd like to generate a single
column unique key that's derived from all the data, so a simple sequential
number primary key won't do. Any tips on how I could do this in Ruby?

Chris
http://clabs.org