I'm stumped. I keep getting a Called id for nil error Assume i have the following models:
class User < ActiveRecord::Base
self.primary_key = 'name'
attr_accessible :name
has_many :projects, :through => :user_projects
has_many :user_projects
end
class UserProject < ActiveRecord::Base
belongs_to :user
belongs_to :project
after_save do |r|
puts r.user.id #<<<<<error here!
end
end
class Project < ActiveRecord::Base
attr_accessible :name#, :body
has_many :user_projects
has_many :users, :through=> :user_projects
# attr_accessible :title, :body
end
and the following migrations:
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :name
t.timestamps
end
end
end
class CreateProjects < ActiveRecord::Migration
def change
create_table :projects do |t|
t.string :name
t.timestamps
end
end
end
class CreateUserProjects < ActiveRecord::Migration
def change
create_table :user_projects do |t|
t.references :user
t.references :project
t.timestamps
end
end
end
running something like :
#project = Factory.create(:project)
#user = Factory.create(:user)
#user.projects << #project
I would get this:
RuntimeError: Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id
Why does the the after_save callback break and what can i do to fix it? It seems like i can't refer to the associated user object from the callback at all. However, if i remove
self.primary_key = 'name'
from the User model, everything works fine. I'm missing something but i don't know what.
Thanks in advance! btw im on rails 3.2.6.
Try to set id to false in your migration like this :
class CreateUsers < ActiveRecord::Migration
def change
create_table :users, :id => false do |t|
t.string :name
t.timestamps
end
end
end
Thanks for the inspiration Dougui! i figured it out. the t.references :project helper defaults the foreign_key to an integer. I changed it manually to the correct type. So now it works!
YaY
class CreateUserProjects < ActiveRecord::Migration
def change
create_table :user_projects do |t|
t.string :user_id #<<<<<<< STRING!!
t.references :project
t.timestamps
end
end
end
Related
I have 2 Models with association has_many along with cascade property between them.
class ServicesBrandDetail < ApplicationRecord
has_many :services_brands, foreign_key: "brand_id", dependent: :delete_all
end
class ServicesBrand < ApplicationRecord
belongs_to :services_brand_details, foreign_key: "brand_id",
end
Migration for both files
class CreateServicesBrandDetails < ActiveRecord::Migration[6.1]
def change
create_table :services_brand_details do |t|
t.string :brand
t.string :mail_list
t.string :cc_list
t.timestamps
end
end
end
class CreateServicesBrands < ActiveRecord::Migration[6.1]
def change
create_table :services_brands do |t|
t.string :warehouse
t.references :brand, null: false, foreign_key: {to_table: :services_brand_details}
t.timestamps
end
end
end
Now I was able to create and save data in from ServicesBrandDetails model. but the Problem is when i create record from ServiceBrand It created record perfectly but i was not able to store data in DB.
record = ServicesBrandDetail.create(:brand => "a", :mail_list => 'abc#mail.com', :cc_list => 'def#mail.com')
record.save
Record successfully stored in DB.
child = record.services_brands.new(:warehouse => "in") <-- record was created successfully.
child.save
it give me error
C:/Ruby30-x64/lib/ruby/gems/3.0.0/gems/activerecord-6.1.5/lib/active_record/inheritance.rb:237:in `compute_type': uninitialized constant ServicesBrand::ServicesBrandDetails (NameError)
Please follow proper Naming convention
This article might help - https://www.bigbinary.com/learn-rubyonrails-book/summarizing-rails-naming-conventions
In ServiceBrand Model
class ServiceBrand < ApplicationRecord
belongs_to :brand, class_name: 'ServiceBrandDetail'
end
belongs_to should be foreign key name i.e brand in your case
You can delete existing models and tables from your codebase and try below one. (I've tested)
class ServiceBrandDetail < ApplicationRecord
has_many :service_brands, foreign_key: :brand_id, dependent: :delete_all
end
class ServiceBrand < ApplicationRecord
belongs_to :brand, class_name: 'ServiceBrandDetail'
end
Migration for both files
class CreateServiceBrandDetails < ActiveRecord::Migration[6.1]
def change
create_table :service_brand_details do |t|
t.string :brand
t.string :mail_list
t.string :cc_list
t.timestamps
end
end
end
class CreateServiceBrands < ActiveRecord::Migration[6.1]
def change
create_table :service_brands do |t|
t.string :warehouse
t.references :brand, null: false, foreign_key: {to_table: :service_brand_details}
t.timestamps
end
end
end
Then try to create model objects which you tried in your question. It will work 👍🏽
In your model ServicesBrand you have to use singular association name for belongs_to
Change this belongs_to :services_brand_details to this belongs_to :services_brand_detail
class ServicesBrand < ApplicationRecord
belongs_to :services_brand_detail, foreign_key: "brand_id"
end
I find this issue when I try to save the a team, how can I solve it? I am trying to deal with these associations for so long, if you guys do other issues, just let me know, please (this association has been a nightmare).
Here are the models
class Field < ApplicationRecord
end
class Game < ApplicationRecord
belongs_to :field
belongs_to :organiser
has_one :team
has_many :players, through: :team
end
class Organiser < ApplicationRecord
has_many :games
end
class Player < ApplicationRecord
has_many :teams
has_many :games, through: :teams
end
class Team < ApplicationRecord
has_many :players
belongs_to :game
end
Here are the migrations
class CreateOrganisers < ActiveRecord::Migration[5.2]
def change
create_table :organisers do |t|
t.string :name
t.string :email
t.integer :age
t.timestamps
end
end
end
class CreatePlayers < ActiveRecord::Migration[5.2]
def change
create_table :players do |t|
t.string :name
t.integer :age
t.string :address
t.timestamps
end
end
end
class CreatePlayers < ActiveRecord::Migration[5.2]
def change
create_table :players do |t|
t.string :name
t.integer :age
t.string :address
t.timestamps
end
end
end
class CreateFields < ActiveRecord::Migration[5.2]
def change
create_table :fields do |t|
t.string :location
t.string :transports
t.timestamps
end
end
end
class CreateGames < ActiveRecord::Migration[5.2]
def change
create_table :games do |t|
t.references :field, foreign_key: true
t.references :organiser, foreign_key: true
t.integer :size
t.timestamps
end
end
end
class CreateTeams < ActiveRecord::Migration[5.2]
def change
create_table :teams do |t|
t.references :player, foreign_key: true
t.references :game, foreign_key: true
t.timestamps
end
end
end
class AddTeamToGames < ActiveRecord::Migration[5.2]
def change
add_column :games, :team, :reference
end
end
The idea is to make sure that each game will have a team of certain people. I want to access the people through game.team.player
Your migrations doesn't have any kind of references to connect these tables.
For example Game has_one :team is not going to create this references for you, to call game.team needs a column called game_id in teams table.
To add the reference you can create a migration for it:
rails g migration AddGameToTeams game:references
This will create that migration file may look like this:
class AddGameToTeams < ActiveRecord::Migration
def change
add_reference :teams, :game, index: true
end
end
Depending in the version you running rails this migration file may differ a little with adding an extra line regarding foreign_key.
Run the generated migration with rails db:migrate and it should work.
You need to apply the same concept to the rest of your tables.
Hope this helps.
I'm working on a twitter clone and have been having trouble with some of my associations. I want a user to have many tweets. My tweets will have a many-to-many relationship with hashtags, so in theory I want to be able to call User.find(1).hashtags and have a list of the user's hashtags (edit: solved this issue). I also am having trouble pushing hashtags into a specific tweet.
Here are my models:
class User < ActiveRecord::Base
has_many :tweets
end
class Tweet < ActiveRecord::Base
belongs_to :user
has_and_belongs_to_many :hashtags
end
class Hashtag < ActiveRecord::Base
has_and_belongs_to_many :tweets
end
Here are my migrations:
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :username
t.string :email
t.string :password
t.timestamps
end
end
end
class CreateTweets < ActiveRecord::Migration
def change
create_table :tweets do |t|
t.string :content
t.belongs_to :user
t.timestamps
end
end
end
class CreateHashtags < ActiveRecord::Migration
def change
create_table :hashtags do |t|
t.string :tag
t.timestamps
end
end
end
class CreateHashtagsTweets < ActiveRecord::Migration
def change
create_table :hashtags_tweets, id: false do |t|
t.references :hashtag
t.references :tweet
end
end
end
Any help would be greatly appreciated! Thanks!
Why is the associated record id not saved?
Diagram of database
Console error message
Teacher Migration
class CreateTeachers < ActiveRecord::Migration
def change
create_table :teachers do |t|
t.string :name
t.belongs_to :classroom
t.timestamps
end
end
end
Classrooms migration
class CreateClassrooms < ActiveRecord::Migration
def change
create_table :classrooms do |t|
t.string :name
t.timestamps
end
end
end
model/teacher.rb
class Teacher < ActiveRecord::Base
belongs_to :classroom
end
model/classroom.rb
class Classroom < ActiveRecord::Base
has_one :teacher
end
app/admin/teacher.rb
ActiveAdmin.register Teacher do
permit_params{
:id
:classroom_id
:name
}
end
I guess you forget comas in permit_params :
ActiveAdmin.register Teacher do
permit_params{
:id,
:classroom_id,
:name
}
end
I've got a problem with a has_many :through association, i cant call the u1.UsersProfileAttributes.find_by_ProfileAttribute_name("icq") method, rails means that this method doesn't exist. The method u1.UsersProfileAttributes.find_by_ProfileAttribute_id(3) works correctly. u1 is a user object. I don't know whats the problem, because my associations seems to be okay. Have a look:
class ProfileAttribute < ActiveRecord::Base
has_many :UsersProfileAttributes
has_many :users, :through => :UsersProfileAttributes
end
class User < ActiveRecord::Base
has_many :UsersProfileAttributes
has_many :ProfileAttributes, :through => :UsersProfileAttributes
end
class UsersProfileAttribute < ActiveRecord::Base
belongs_to :user
belongs_to :ProfileAttribute
end
My Migration file:
class CreateProfileAttributes < ActiveRecord::Migration
def self.up
create_table :profile_attributes do |t|
t.string :name
t.integer :profile_group_id
t.timestamps
end
create_table :users_profile_attributes do |t|
t.integer :user_id
t.integer :ProfileAttribute_id
t.string :value
end
end
def self.down
drop_table :profile_attributes
drop_table :users_profile_attributes
end
end
You need to query ProfileAttributes, not UsersProfileAttributes. This should work for you: u1.ProfileAttributes.find_by_name('icq')
u1.UsersProfileAttributes.find_by_ProfileAttribute_id(3) works because ProfileAttribute_id is an attribute of UsersProfileAttribute ... so ActiveRecord builds you a dynamic finder.
u1.UsersProfileAttributes.find_by_ProfileAttribute_name("icq") does not work because ProfileAttribute_name is not an attribute of UsersProfileAttribute.