I have a model with associations. How to create/update the associations as CRUD operations are performed on the model.
That is, when I run
#v1_seller = V1::Seller.new(seller_params)
#v1_seller.save
It should save the associations.
Should I create after_create hooks and pass the params (but then I will have to do the same in update)? Or am I missing something? I feel that it should be done automatically in rails.
currently I am doing it explicitly:
#v1_seller = V1::Seller.new(seller_params)
if #v1_seller.save
#v1_seller.assign_categories(params)
my seller model:
class V1::Seller < ActiveRecord::Base
has_many :categories, :class_name => 'V1::Category', dependent: :delete_all
has_many :category_names, :class_name => 'V1::CategoryName', through: :categories
# right now I am manually calling this after a create/update operation in my controller
def assign_categories(params)
params.require(:seller).require(:categories)
params.require(:seller).permit(:categories => []).permit(:name, :brands => [])
self.categories.clear
params[:seller][:categories].each do |c|
if c[:brands].nil? || c[:brands].empty?
next # skip the category if it has no brands associated with it
end
category_name = c[:name]
category = V1::Category.new
category.category_name = V1::CategoryName.find_by(name: category_name)
category.seller = self
category.save
c[:brands].each do |b|
begin
category.brand_names << V1::BrandName.find_by(name: b)
rescue ActiveRecord::RecordInvalid
# skip it. May happen if brand is already added to the particular category
end
end
end
end
end
And V1::Cateogry model:
class V1::Category < ActiveRecord::Base
belongs_to :category_name, :class_name => 'V1::CategoryName', inverse_of: :category
belongs_to :seller, :class_name => 'V1::Seller', inverse_of: :category
has_many :brands, :class_name => 'V1::Brand', dependent: :delete_all, inverse_of: :category
has_many :brand_names, :class_name => 'V1::BrandName', through: :brands, inverse_of: :category
validates :seller, :uniqueness => {:scope => [:category_name, :seller]}
end
Seem like you need nested attributes.
Checkout the docs here: http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html
Related
I have the following models:
class Article < ActiveRecord::Base
has_many :comments, :as => :subject, :dependent => :destroy
has_many :deleted_comments, :as => :subject, :dependent => :destroy
end
class DeletedComment < ActiveRecord::Base
belongs_to :subject, :polymorphic => true
end
class Comment < ActiveRecord::Base
belongs_to :subject, :polymorphic => true
before_destroy :create_deleted_comment
def create_deleted_comment
DeletedComment.create!(....)
end
end
In my database, I have quite a few DeletedComment objects where the subject is nil. The DeletedComment (and Comment) model stores :article_id, and for the ones where the subject is nil, Article.find(deleted_comment.article_id) raises an ActiveRecord::RecordNotFound error.
Are there any cases where the :dependent => :destroy would destroy the parent record but leave the dependencies untouched?
Is it possible that in some cases when I delete an Article the deleted_comments are destroyed before comments? and when the comments are destroyed, deleted_comments are created and not destroyed (because ActiveRecord has already checked the dependent deleted_comment and tried to destroy any dependencies)?
According to official documentation:
Using polymorphic associations in combination with single table inheritance (STI) is a little tricky. In order for the associations to work as expected, ensure that you store the base model for the STI models in the type column of the polymorphic association. To continue with the asset example above, suppose there are guest posts and member posts that use the posts table for STI. In this case, there must be a type column in the posts table.
class Asset < ActiveRecord::Base
belongs_to :attachable, polymorphic: true
def attachable_type=(sType)
super(sType.to_s.classify.constantize.base_class.to_s)
end
end
class Post < ActiveRecord::Base
# because we store "Post" in attachable_type now dependent: :destroy will work
has_many :assets, as: :attachable, dependent: :destroy
end
class GuestPost < Post
end
class MemberPost < Post
end
I guess you could use examle and do something like:
class Article < ActiveRecord::Base
# for deletion only
has_many :abstract_comments, :as => :subject, :dependent => :destroy
# for 'manual' access/edition
has_many :comments, :as => :subject
has_many :deleted_comments, :as => :subject
end
class AbstractComment < ActiveRecord::Base
belongs_to :subject, :polymorphic => true
def attachable_type=(sType)
super(sType.to_s.classify.constantize.base_class.to_s)
end
end
class DeletedComment < AbstractComment
end
class Comment < AbstractComment
before_destroy :create_deleted_comment
def create_deleted_comment
DeletedComment.create!(....)
end
end
I generated namespaced models and how can i set many-to-many
relationships, category has many posts, post has many categories
rails g model Blog::Post body:text, title:string
rails g model Blog::Category title:string
rails g model Blog::CategoryPost post_id:integer, category_id:integer
and my models looks like
class Blog::Category < ActiveRecord::Base
attr_accessible :title
has_many :posts, :class_name => 'Blog::Post', :through => :blog_categories_posts
end
class Blog::CategoryPost < ActiveRecord::Base
belongs_to :category, :class_name => 'Blog::Category'
belongs_to :post, :class_name => 'Blog::Post'
end
class Blog::Post < ActiveRecord::Base
attr_accessible :body, :title
has_many :categories, :class_name => 'Blog::Category', :through => :blog_categories_posts
end
This should work. You need to specify relation to intermediate table.
class Blog::Category < ActiveRecord::Base
attr_accessible :title
has_many :categories_posts, :class_name => 'Blog::CategoryPost'
has_many :posts, :class_name => 'Blog::Post', :through => :categories_posts
end
class Blog::CategoryPost < ActiveRecord::Base
belongs_to :category, :class_name => 'Blog::Category'
belongs_to :post, :class_name => 'Blog::Post'
end
class Blog::Post < ActiveRecord::Base
attr_accessible :body, :title
has_many :categories_posts, :class_name => 'Blog::CategoryPost'
has_many :categories, :class_name => 'Blog::Category', :through => :categories_posts
end
Try adding the associations to the CategoryPosts to the Category and Post models. eg:
class Blog::Category < ActiveRecord::Base
...
has_many :blog_category_posts, :class_name => "Blog::CategoryPost"
...
end
I believe you need to do this for both the Category and the Post models.
My db schema:
tournaments(id, ...)
teams(tournament_id, id, ...)
matches(tournament_id, id, team_id_home, team_id_away, ...)
Models:
class Tournament < ActiveRecord::Base
has_many :teams, dependent: :destroy
has_many :matches, dependent: :destroy
...
end
class Team < ActiveRecord::Base
belongs_to :tournament
...
end
class Match < ActiveRecord::Base
belongs_to :tournament
has_many :teams
...
end
I would like to have the following data in my view:
match_id team_id_home team_id_away team_id_home_name team_id_away_name
So, I'm asking for help with the following query (I'm trying to get team's names, but having problem with joining):
#matches = #tournament.matches.where(:tournament => #tournament).joins(:teams).paginate(page: params[:page])
I'm fairly new to rails, but you should be able to setup your associations like this: (going from memory)
class Match < ActiveRecord::Base
belongs_to :tournament
has_one :home_team, :class_name => "Team", :foreign_key => "team_id_home"
has_one :away_team, :class_name => "Team", :foreign_key => "team_id_away"
end
#####
m = Match.first
m.away_team.team_name
m.home_tam.team_name
Or in your case:
#matches = #tournament.matches.paginate(page: params[:page])
I don't think you need the where function: the has_many association tells rails to only pull matching matches.
It is belongs_to, not has_one in Match model.
class Match < ActiveRecord::Base
belongs_to :tournament
belongs_to :home_team, :class_name => "Team", :foreign_key => "team_id_home"
belongs_to :away_team, :class_name => "Team", :foreign_key => "team_id_away"
end
class Team < ActiveRecord::Base
belongs_to :tournament
has_many :matches
end
Now I can use tournament.home_team.name in my view
I'm currently modeling a Rails 3.2 app and I need a polymorphic association named "archivable" in a table named "archives". No worries with it, but my "archives" table must also belongs_to a "connections" table. I just want to know if there's any constraints from Rails to do that.
You can see the model here
Another detail, my Connection model has twice user_id as foreign key. A user_id as sender and a user_is as receiver. Possible? I think what I did below won't work...
Here are my models associations.
class User < ActiveRecord::Base
has_many :connections, :foreign_key => :sender
has_many :connections, :foreign_key => :receiver
end
class Connections < ActiveRecord::Base
belongs_to :user
has_many :archives
end
class Archive < ActiveRecord::Base
belongs_to :connection
belongs_to :archivable, :polymorphic => true
end
class Wink < ActiveRecord::Base
has_many :archives, :as => :archivable
end
class Game < ActiveRecord::Base
has_many :archives, :as => :archivable
end
class Message < ActiveRecord::Base
has_many :archives, :as => :archivable
end
Do you see anything wrong or something not doable with Rails?
Thank you guys.
I think you want to do this :
class Connections
belongs_to :sender, :class_name => 'User', :foreign_key => 'sender_id'
belongs_to :receiver, :class_name => 'User', :foreign_key => 'receiver_id'
end
class User
has_many :sended_connections, :class_name => 'Connection', :as => :sender
has_many :received_connections, :class_name => 'Connection', :as => :receiver
end
Important : Don't declare 2 times has_many :connections with the same name !
I've got users and organisations with a join model UsersOrganisation. Users may be admins of Organisations - if so the is_admin boolean is true.
If I set the is_admin boolean by hand in the database, Organisations.admins works as I'd expect.
In the console, I can do Organisation.first.users << User.first and it creates an organisations_users entry as I'd expect.
However if I do Organisation.first.admins << User.last it creates a normal user, not an admin, ie the is_admin boolean on the join table is not set correctly.
Is there a good way of doing this other than creating entries in the join table directly?
class User < ActiveRecord::Base
has_many :organisations_users
has_many :organisations, :through => :organisations_users
end
class Organisation < ActiveRecord::Base
has_many :organisations_users
has_many :users, :through => :organisations_users
has_many :admins, :through => :organisations_users, :class_name => "User",
:source => :user,
:conditions => {:organisations_users => {:is_admin => true}}
end
class OrganisationsUser < ActiveRecord::Base
belongs_to :organisation
belongs_to :user
end
You can always override the << method of the association:
has_many :admins do
def <<(user)
user.is_admin = true
self << user
end
end
(Code has not been checked)
there are some twists with the has_many :through and the << operator. But you could overload it like in #Erez answer.
My approach to this is using scopes (I renamed OrganisationsUsers to Memberships):
class User < ActiveRecord::Base
has_many :memberships
has_many :organisations, :through => :memberships
end
class Organisation < ActiveRecord::Base
has_many :memberships
has_many :members, :through => :memberships, :class_name => 'User', :source => :user
# response to comment:
def admins
memberships.admin
end
end
class Memberships < ActiveRecord::Base
belongs_to :organisation
belongs_to :user
scope :admin, where(:is_admin => true)
end
Now I create new admins like this:
Organisation.first.memberships.admin.create(:user => User.first)
What I like about the scopes is that you define the "kind of memberships" in the membership class, and the organisation itself doesn't have to care about the kinds of memberships at all.
Update:
Now you can do
Organisation.first.admins.create(:user => User.first)
You can try below code for organization model.
class Organisation < ActiveRecord::Base
has_many :organisations_users
has_many :organisations_admins, :class_name => "OrganisationsUser", :conditions => { :is_admin => true }
has_many :users, :through => :organisations_users
has_many :admins, :through => :organisations_admins, :source => :user
end