find_or_create_by in Rails 3 and updating for creating records

Question

I\'m not sure if I should be updating records this way or if I\'m missing something.

I have a table with 5 columns (not including timestamps and id) 3 of which are d

Answer 1

Here is two approaches.

First you can extend Available with exact method you need:

def self.find_or_create_by_room_id_and_bookdate_and_source(room_id, bookdate, source, &block)
  obj = self.find_by_room_id_and_bookdate_and_source( room_id, bookdate, source ) || self.new(:room_id => room_id, :bookdate => bookdate, :source => source)
  yield obj
  obj.save
end

usage

Available.find_or_create_by_room_id_and_bookdate_and_source(room.id, (params[:date].to_date)+index, data.class.to_s) do |c|
  c.price = night.price
  c.spots = night.spots
end

This is awkward. So for being more flexible you can create update_or_create_by... method for ActiveRecord using method_missing magic:

class ActiveRecord::Base
  def self.method_missing(method_id, *args, &block)
    method_name = method_id.to_s
    if method_name =~ /^update_or_create_by_(.+)$/
      update_or_create($1, *args, &block)
    else
      super
    end
  end
  def self.update_or_create(search, *args, &block)
    parameters = search.split("_and_")
    params = Hash[ parameters.zip(args) ]
    obj = where(params).first || self.new(params)
    yield obj
    obj.save
    obj
  end
end

So now you can use it:

Available.update_or_create_by_id_and_source(20, "my_source") do |a|
  a.whatever = "coooool"
end

Answer 2

I think the simplest way is using Ruby's tap method, like this:

def self.parse_data(params,data)
  data.beds.each do |bed|
    room = Room.find_or_create_room(bed.title, params[:id])

    bed.nights.each_with_index do |night,index|
      Available.find_or_initialize_by(room_id: room.id).tap do |available|
        available.bookdate = (params[:date].to_date) + index
        available.source = data.class.to_s
        available.price = night.price
        available.save
      end
    end
  end
end

find_or_initialize_by finds or intitializes a record, then returns it. We then tap into it, make our updates and save it to the database.

Answer 3

Actually, there is a way without any hacking. Instead of find_or_create_by you can use find_or_initialize_by and set updated atributes with tap

Available.find_or_initialize_by_room_id_and_bookdate_and_source(
  room.id, 
  (params[:date].to_date)+index, 
  data.class.to_s#
).tap do |a|
  a.price = night.price
  a.spots = night.spots
end.save!

Initially this can seems cluttered, but it is doing exactly what you asked for. Find the record, instanciate it if not found and update atributes. this could be called "find_and_update_or_create_by", fortunatelly nobody did that. ;) Hope this help.