# File lib/flexirecord.rb, line 856
856:       def copy_primary_key
857:         synchronize do
858:           @old_primary_key.clear
859:           self.class.primary_columns.each do |column|
860:             @old_primary_key[column] = self.read(column)
861:           end
862:         end
863:         nil
864:       end