CODEWITHSUNDEEP
ruby-on-railsactiverecord
Syn
Syn

Reputation: 1128

Rails activerecord saved data are all nil/null

I am a beginner in all this and I am trying to build a very basic controller.

This is my write/create method:

It checks if an id is included in the params. If there is an ID, it does a put request to update an existing car. Otherwise, it just creates a new Car.

def write
    if params[ :id ]
      @car = Car.where( id: params[ :id ] ).first
      params[ :car ].each do | key, value |
        attribute = { "#{ key }": value }
        @car.update_attributes( attribute )
      end
    else
      @car = Car.new( 
                model: params[ :model ], 
                num_wheels: params[ :num_wheels ], 
                color: params[ :color ], 
                realm_uuid: params[ :realm_uuid ] 
              )      
    end

    @car.save!
    render json: @car
  end

This is my routes.rb file:

Rails.application.routes.draw do

  scope '/api' do
    get '/' => 'cars#query'
    post '/' => 'cars#write'

    scope '/:id' do
      get '/' => 'cars#read'
      put '/' => 'cars#write'
      delete '/' => 'cars#delete'
    end
  end

end

And finally my car.rb:

class Car < ApplicationRecord

    attr_accessor :model, :num_wheels, :color, :realm_uuid

end

All the routes work correctly, I can create, read, update, and delete. The thing is that when I read, all the values are nil/null. When I make a post in Postman, the render json: @car returns a correct car with all the values but when I make a get request, it says all the values are nil/null.

I also see an error: ArgumentError (Wrong number of arguments (given 1, expected 4) This probably has something to do with it...

Upvotes: 1

Views: 1024

Answers (1)

Vasfed
Vasfed

Reputation: 18454

attr_accessor on a model makes an reader/writer method for instance variable with corresponding name.

In your case it overrides getter/setters for model attributes and thus you write to variable instead of attribute. So remove attr_accessor and model should save correctly.

If you do not have these fields in db - then you should make a migration to add them.

Upvotes: 3

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