# Reset the primary key to allow us to create robots with specific internal_ids class Robot < ActiveRecord::Base set_primary_key :id end Robot.create :name => 'Fritz', :internal_id => 'F0001' Robot.create :name => 'Sizzle', :internal_id => 'S0001' Robot.create :name => 'Sizzle Jr.', :internal_id => 'S0002' Robot.create :name => 'Expendable', :internal_id => 'E0001' # Annnnnnnnnnd we're back class Robot < ActiveRecord::Base set_primary_key :internal_id end