Add simple CRUD (Bike, Gps_record)

• data logics:

  • (v) bikes has a unique name
  • (v) bikes can update gps records
  • (v) gps records creates when assosicated bike created
  • (v) gps record can not be edit, update, destroy
  • (v) gps record can be destroy when assosicated bike destroy

• Views logics:

  • (v) has a homepage with link to create bike, add gps_record to bike, destroy bike
  • (v) has a index of bikes with last gps record updates in home page
  • (v) has a page for bike create
  • (v) has a page for bike to add gps record

known problem

• N+1 problem

note: some error happen when coding (cost me a lot of time)

• when models assosicated.should noitice belong_to should be odd, has_many should be plural
• still don't get it why: def create @bike = Bike.new(bike_params) @bike_gps = @bike.gps_records.new if @bike.save redirect_to root_path, notice: 'You just create a AWESOME bike!' else flash.now[:notice] = 'bike name existed, please rename your bike' render :new end end

1. why @bike_gps will also save into database (:gps_records) even if didn't @bike_gps.save
2. if i markup '@bike_gps = @bike.gps_records.new', and there's nothing create at database