i'm trying to figure out the proper way to do this, but if i have 2 models, how do I get the data from the 1st Model in the 2nd MVC. Example:
Model 1: User
Model 2: Post
I have a "user_id" field in the Post Model. If I am in the Post Controller/View, how do I fetch the user's first and last name from Model 1?
Thanks so much in advance!
Set a user association in the Post model:
class Post < ActiveRecord::Base
belongs_to :user
end
class User < ActiveRecord::Base
has_many :posts
end
Then it is as easy as:
post.user.first_name
Look up associations - With Active Record associations, we can streamline these - and other - operations by declaratively telling Rails that there is a connection between the two models.-- http://guides.rubyonrails.org/association_basics.html
class User < ActiveRecord::Base
has_many :posts
end
class Post < ActiveRecord::Base
belongs_to :user
end
Related
I have 3 models:
class Repositioning < ActiveRecord::Base
has_one :repo_mood
has_one :mood, through: :repo_mood
end
class Mood < ActiveRecord::Base
has_many :repo_moods
has_many :repositionings, through: :repo_moods
end
class RepoMood < ActiveRecord::Base
belongs_to :repositioning
belongs_to :mood
end
But I only have a Repositionings controller. In my app, the user can add a mood to the repositioning and the data is sent to my API as:
repositioning: { mood: mood_id }
Is there a railsy way of generating the necessary repo_mood entry:
RepoMood.create(repositioning_id: repositioning.id, mood_id: mood_id)
without manually calling it? I'm thinking like nested forms in a Rails view.
You'll want accepts_nested_attributes_for to do this.
It'll allow you to create related models simply by passing the proper attributes to your API endpoint.
I want to model different post types
ImagePost VideoPost TextPost. They all have different contents
I was going to go with post has_many polymorphic but rails doesn't support it
A previous stackoverflow post pointed me towards has_many_polymorphs gem but is deprecated
I need to be able to post different posts types and retrieve them in an instance show them on a feed
e.g.
#posts.each do ..
if type == video ...
elseif type == image ....
I'm new to rails so thanks for the assistance.
Use single table inheritance of Post model
class class Post < ActiveRecord::Base
.....
end
Than inherit this Post model into these model.
class VideoPost < Post
end
class ImagePost < Post
end
At migration you need to create a type column for different type of post. For details look at this blog post
Consider doing the following
class Post < ActiveRecord::Base
# Create the an association table and add additional info on the association table, description, etc etc.
has_many :images, through: image_posts
has_many :image_posts
end
class Image < ActiveRecord::Base
# Image specific
end
Doing this, #post.image_posts.count > 0 indicates there are multiple image_posts.
Or you could also achieve the goal by polymorphic relation:
class VideoPost < ActiveRecord::Base
belongs_to :postable, polymorphic: true
end
class ImagePost < ActiveRecord::Base
belongs_to :postable, polymorphic: true
end
class Feed < ActiveRecord::Base
has_many :posts, as: :postable
end
In this case #feed.posts.each will check the postable_type, which is the model type instead.
STI is the way to go. I guess columns of all three type should be same or similar at least. So Single tale inheritance would be the best choice.
I am having issues setting up model relations in Rails.
I have a User. A user can have many requests. A request can have one response. I set up my models like this:
Class User < ActiveRecord::Base
has_many :user_requests
has_many :request_responses, through: :user_requests
end
Class UserRequest < ActiveRecord::Base
belongs_to :user
has_one :request_response
end
Class RequestResponse < ActiveRecord::Base
belongs_to :user_request
end
Whenever I try to do something like:
UserRequest.request_response.id
I get errors that say either the relationship doesn't exist or the column does not exist in the table. Have I set up my relationships incorrectly?
You will get error:
UserRequest.request_response.id
Because:
request_response is expected to be a class method of UserRequest.
Association is defined as request_responses, not request_response, so calling user. request_response won't work either.
What to do?
call user.request_response_ids where user = User.first.
I was wondering how I'm suppose to associate my User, Post, and Comment models. It is suppose to be like so: The user can comment on any post and a post belongs to a user with a Boolean for being admin. I have been scratching my had for awhile trying to figure this out but nothing has made any sense at all.
Any help would be greatly appreciated.
In the most obvious arrangement Post would belong_to :user and has_many :comments, and Comment would both belong_to :user and belong_to :post. User would has_many :posts.
You can specify the following association in the model
# app/models/comment.rb
class Comment < ActiveRecord::Base
belongs_to :post
belongs_to :user
end
# app/models/user.rb
class User < ActiveRecord::Base
has_many :comments
end
# app/models/post.rb
class Post < ActiveRecord::Base
belongs_to :user
has_many :comments
end
I'm trying to figure out how to best way to create associations for the following models:
User
Category
Post
Comments
Here are the requirements I'm trying to meet:
A user can have many posts
A post belongs to a user
A post can have many comments
A comment belongs to a post
A post can belong to a category
A user does NOT have many categories.
(The number of categories is fixed and the same for all users)
A category can have many posts
In terms of routing, I'd like to be able to access a post within a certain category for a specific user. For example:
http://domain.com/users/1/categories/1/posts
Since there is no direct relationship between User and Category, I'm not quite sure how to best set up the associations. And I'm totally lost on how to configure the routes.
Here's what I have for my models:
class User < ActiveRecord::Base
has_many :posts
end
class Category < ActiveRecord::Base
has_many :posts
end
class Post < ActiveRecord::Base
belongs_to :user
belongs_to :metric
has_many :comments
end
class Comments < ActiveRecord::Base
belongs_to :post
end
Is this a case where I should be using has_many :through relationships? Or something more complex like polymorphic associations? Thanks in advance!
Yes, it would be a very good idea to use :
User has_many :comments, :through => :posts
If you like, you can also get categories comments, by :
Category has_many :comments, :through => :posts
Remember that a through association is just a facility that allows you to do things like user.comments directly (and through is the way for the association to find the user comment that is referred to post model).