importer.rb

class Importer
  CONN = ActiveRecord::Base.connection
  F = "00F"
  I = "00I"

  def extract_to_database(collection) # collection is a file
    add       = true
    tmp       = []
    type      = F
    inserts   = []
    f         = []

    collection.each_with_index do |line, i|
      _type    = line.strip
      _changed = [F,I].include? _type

      if _changed && i > 0
        case type
        when F then f << tmp
        when I
          inserts.push "(#{tmp[1]},'#{tmp[2]}','#{tmp[3]}')"
        end

        tmp  = []
        type = _type
      end

      tmp << line
    end
    sql = "INSERT INTO products (`code`, `name`, `price`) VALUES #{inserts.join(", ")}"
    CONN.execute sql
  end
end

Code  | Name  | Price
00106 | Water | 9.99
00107 | Onion | 8.99

Which is coded in GES file like below:

• 00F means column header
• 00I means insert a row
  there are also others like(00D for delete row or 00U for update)

00F
0101
02Code
031
00F
0102
02Name
031
00F
0103
02Price
030
00I
0100106
02Water
030999
00I
0100107
02Onion
030899

Check a refactor in my fork of the gist. Note that "f" is not used anywhere so I removed it. I used a model Product, if you are using AR it makes no sense to use raw SQL. The key to make it functional is using each_slice.