Here's my self referential model and it's two join tables:
class Discourse < ActiveRecord::Base
belongs_to :forum
belongs_to :user
has_many :impressions
has_many :discourse_replies
has_many :replies, through: :discourse_replies
has_many :reply_retorts
has_many :retorts, through: :reply_retorts
end
class DiscourseReply < ActiveRecord::Base
belongs_to :discourse
belongs_to :reply, class_name: 'Discourse', foreign_key: 'reply_id'
end
class ReplyRetort < ActiveRecord::Base
belongs_to :reply
belongs_to :retort, class_name: 'Discourse', foreign_key: 'retort_id'
end
It seems to be working well...I can do this in the rails console:
2.0.0p247 :044 > fd = Discourse.create(title: 'first', body: 'first')
=> #<Discourse id: 139, user_id: nil, title: "first", body: "first", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:38:06", updated_at: "2014-04-07 20:38:06", forum_id: nil>
2.0.0p247 :046 > fdr = fd.replies.create(title: 'second relpy to first', body: 'second reply to first')
=> #<Discourse id: 141, user_id: nil, title: "second relpy to first", body: "second reply to first", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:38:51", updated_at: "2014-04-07 20:38:51", forum_id: nil>
2.0.0p247 :047 > fdrr = fdr.retorts.create(title: 'a reply to a reply', body: 'a reply to a reply')
=> #<Discourse id: 142, user_id: nil, title: "a reply to a reply", body: "a reply to a reply", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:39:27", updated_at: "2014-04-07 20:39:27", forum_id: nil>
2.0.0p247 :048 > fdrrr = fdrr.retorts.create(title: 'a reply to a reply to a reply', body: 'a reply to a reply reply')
=> #<Discourse id: 143, user_id: nil, title: "a reply to a reply to a reply", body: "a reply to a reply reply", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:39:47", updated_at: "2014-04-07 20:39:47", forum_id: nil>
2.0.0p247 :050 > fdr.retorts
=> #<ActiveRecord::Associations::CollectionProxy [#<Discourse id: 142, user_id: nil, title: "a reply to a reply", body: "a reply to a reply", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:39:27", updated_at: "2014-04-07 20:39:27", forum_id: nil>]>
However, I need to find out the parent association, but can't figure out how to do it:
2.0.0p247 :053 > fdr.discourse # I want this to return the 'fd' instance
NoMethodError: undefined method `discourse` for #<Discourse:0x00000007080eb0>
2.0.0p247 :055 > fdrrr.reply # I want this to return the 'fdrr' instance
NoMethodError: undefined method `reply` for #<Discourse:0x000000070db860>
2.0.0p247 :055 > fdrrr.parent # I want this to return the 'fdrr' instance
NoMethodError: undefined method `parent' for #<Discourse:0x0000000672b428>
2.0.0p247 :055 > fdrrr.parent.try(:id) # I want this to return the 'fdrr' instance
NoMethodError: undefined method `parent' for #<Discourse:0x0000000672b428>
Nothing is working!
class Discourse < ActiveRecord::Base
def reply
DiscourseReply.where(reply_id: id).first.try(:discourse) ||
ReplyRetort.where(retort_id: id).first.try(:reply)
end
alias_method :parent, :reply
alias_method :discourse, :reply
end
But you might want to store the id of the parent on the Discourse model, and maybe have Discourse by polymorphic (using STI)? I feel like it's weird not to be able to tell the type of the object without looking at the associations.
Related
I have two models post and topic which has a one to many relation
#Post.rb
class Post < ApplicationRecord
belongs_to :topic
validates :topic_id, presence: true
validates :title, presence: true
validates :body, presence: true
end
if i have an array of posts by calling Post.all for example
#<ActiveRecord::Relation [#<Post id: 1, title: "Rails Code", body: "class TopicsController < ApplicationController\r\n ...", created_at: "2018-05-22 09:34:15", updated_at: "2018-05-22 09:34:15", topic_id: "2">,
#<Post id: 2, title: "Post with tags", body: "qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq...", created_at: "2018-05-22 11:48:54", updated_at: "2018-05-22 11:48:54", topic_id: "2">,
#<Post id: 3, title: "12hello world12", body: "12312sdfsdfsdsdsdsd31231231231231", created_at: "2018-05-23 12:54:02", updated_at: "2018-05-23 12:54:02", topic_id: "2">,
#<Post id: 4, title: "12hello world12", body: "12312sdfsdfsdsdsdsd31231231231231", created_at: "2018-05-23 12:54:09", updated_at: "2018-05-23 12:54:09", topic_id: "1">,
#<Post id: 5, title: "12hellsdssdo world12", body: "12312sdfsdfsdsdsdsd31231231231231", created_at: "2018-05-23 12:54:15", updated_at: "2018-05-23 12:54:15", topic_id: "1">]>
is there a way i could group them by their topic_id so i could display them topic by topic
example
Topic - 1
post 1 post2 post 3
Topic -2
post4 post5
Use this:
Post.all.group_by(&:topic_id).each do |topic_id, posts|
...
end
Found the answer.
You can do it using ruby's Enumerable#group_by:
post.group_by{|post| post.topic_id}
I`m trying to use String as Primary/Foreign key on a small crawler that I'm making. But I keep receiving the following error when I try to use the Associations methods (eg.: a.crawler_details - Where a is an object called Asin):
RangeError: 8532503039 is out of range for ActiveRecord::Type::Integer with limit 4
Record example:
#<Asin asin: "8532503039", title: "O Físico", image_url: nil, active: false, created_at: "2015-05-04 03:30:29", updated_at: "2015-05-04 03:30:36">
Here are the details:
2.1.2 :001 > Asin.new
=> #<Asin asin: nil, title: nil, image_url: nil, active: true, created_at: nil, updated_at: nil>
2.1.2 :002 > CrawlerDetail.new
=> #<CrawlerDetail id: nil, amazon_price: nil, feed_price: nil, first_place: nil, second_place: nil, third_place: nil, fp_price: nil, sp_price: nil, tp_price: nil, run: nil, created_at: nil, updated_at: nil>
class Asin < ActiveRecord::Base
has_many :crawler_details, :foreign_key => 'id', :primary_key=> 'asin'
self.primary_key = 'asin'
...
end
class CrawlerDetail < ActiveRecord::Base
has_one :asin, :foreign_key => 'asin', :primary_key => 'id'
end
I also tried the belongs_to relation but with no luck. Any ideas here?
I think that is not association error , did you defined field name "asin" type integer in your database table ?
it may help please try to alter your database table from type integer to string .
Am I missing something here?
Discourse model:
class Discourse < ActiveRecord::Base
#<Discourse id:, user_id: , sub_discourse_id: , title: , body: , deleted: , delete_date: , created_at:, updated_at: >
has_many :discourse_replies
has_many :replies, through: :discourse_replies
end
DiscourseReply model:
class DiscourseReply < ActiveRecord::Base
belongs_to :discourse
belongs_to :reply, class_name: 'Discourse'
end
console:
Loading development environment (Rails 4.0.2)
2.0.0p247 :001 > fd = Discourse.create(title: 'first', body: 'first')
=> #<Discourse id: 5, user_id: nil, sub_discourse_id: nil, title: "first", body: "first", deleted: nil, delete_date: nil, created_at: "2014-04-04 23:32:13", updated_at: "2014-04-04 23:32:13">
2.0.0p247 :002 > fd.discourse_replies
=> #<ActiveRecord::Associations::CollectionProxy []>
2.0.0p247 :004 > fd.create_discourse_reply
NoMethodError: undefined method 'create_discourse_reply' for #<Discourse:0x00000003396450>
2.0.0p247 :004 > fd.discourse_replies.build(title: "reply to first", body: "reply to first")
ActiveRecord::UnknownAttributeError: unknown attribute: title
In a nutshell, why is create_discourse_reply an undefined method?
You've defined has_many association for discourse_replies so to create a associated object you need to do
fd.discourse_replies.create
fd.create_discourse_reply would have been created the object if you'd have associated it with has_one or belongs_to association.
Here's my self referential model and it's two join tables:
class Discourse < ActiveRecord::Base
belongs_to :forum
belongs_to :user
has_many :impressions
has_many :discourse_replies
has_many :replies, through: :discourse_replies
has_many :reply_retorts
has_many :retorts, through: :reply_retorts
end
class DiscourseReply < ActiveRecord::Base
belongs_to :discourse
belongs_to :reply, class_name: 'Discourse', foreign_key: 'reply_id'
end
class ReplyRetort < ActiveRecord::Base
belongs_to :reply
belongs_to :retort, class_name: 'Discourse', foreign_key: 'retort_id'
end
It seems to be working well...I can do this in the rails console:
2.0.0p247 :044 > fd = Discourse.create(title: 'first', body: 'first')
=> #<Discourse id: 139, user_id: nil, title: "first", body: "first", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:38:06", updated_at: "2014-04-07 20:38:06", forum_id: nil>
2.0.0p247 :046 > fdr = fd.replies.create(title: 'second relpy to first', body: 'second reply to first')
=> #<Discourse id: 141, user_id: nil, title: "second relpy to first", body: "second reply to first", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:38:51", updated_at: "2014-04-07 20:38:51", forum_id: nil>
2.0.0p247 :047 > fdrr = fdr.retorts.create(title: 'a reply to a reply', body: 'a reply to a reply')
=> #<Discourse id: 142, user_id: nil, title: "a reply to a reply", body: "a reply to a reply", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:39:27", updated_at: "2014-04-07 20:39:27", forum_id: nil>
2.0.0p247 :048 > fdrrr = fdrr.retorts.create(title: 'a reply to a reply to a reply', body: 'a reply to a reply reply')
=> #<Discourse id: 143, user_id: nil, title: "a reply to a reply to a reply", body: "a reply to a reply reply", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:39:47", updated_at: "2014-04-07 20:39:47", forum_id: nil>
2.0.0p247 :050 > fdr.retorts
=> #<ActiveRecord::Associations::CollectionProxy [#<Discourse id: 142, user_id: nil, title: "a reply to a reply", body: "a reply to a reply", deleted: nil, delete_date: nil, created_at: "2014-04-07 20:39:27", updated_at: "2014-04-07 20:39:27", forum_id: nil>]>
However, I need to find out the parent association, but can't figure out how to do it:
2.0.0p247 :053 > fdr.discourse # I want this to return the 'fd' instance
NoMethodError: undefined method `discourse` for #<Discourse:0x00000007080eb0>
2.0.0p247 :055 > fdrrr.reply # I want this to return the 'fdrr' instance
NoMethodError: undefined method `reply` for #<Discourse:0x000000070db860>
2.0.0p247 :055 > fdrrr.parent # I want this to return the 'fdrr' instance
NoMethodError: undefined method `parent' for #<Discourse:0x0000000672b428>
2.0.0p247 :055 > fdrrr.parent.try(:id) # I want this to return the 'fdrr' instance
NoMethodError: undefined method `parent' for #<Discourse:0x0000000672b428>
Nothing is working! However, if I were to set up polymorphic association STI, it work, right? As a nooby this is a bit difficult, especially on such a complex self-referential model, but the answer boils down to this:
What columns to I need to add to my discourses table
and
How should I tweak my relationships?
class Discourse < ActiveRecord::Base
belongs_to :forum
belongs_to :user
has_many :impressions
has_many :discourse_replies
has_many :replies, through: :discourse_replies
has_many :reply_retorts
has_many :retorts, through: :reply_retorts
end
I does not find self-referencing relationship in model 'Discourse'.
If you look at the four method calls below, Service.first returns a Service object, Salon.first returns a Salon object, etc. But TransactionItem.first returns a Service object. Why could this be?
ruby-1.8.7-p334 :001 > Service.first
=> #<Service id: 147, name: "Fub", salon_id: 2, created_at: "2011-08-10 18:00:07", updated_at: "2011-08-10 18:00:12", price: nil, active: true, archived: true>
ruby-1.8.7-p334 :002 > Salon.first
=> #<Salon id: 1, name: "The Cheeky Strut", created_at: nil, updated_at: nil, address_id: nil, email: nil>
ruby-1.8.7-p334 :003 > Product.first
=> #<Product id: 1, name: "Herbal Essences Shampoo", retail_price: #<BigDecimal:10305f1f0,'0.1E2',9(18)>, wholesale_price: nil, sku: "", salon_id: 2, created_at: "2011-07-08 01:35:48", updated_at: "2011-07-08 01:35:48", archived: false>
ruby-1.8.7-p334 :004 > TransactionItem.first
=> #<Service id: 63, created_at: "2011-08-30 20:05:57", updated_at: "2011-08-30 20:05:57", price: #<BigDecimal:10303eba8,'0.18E2',9(18)>>
ruby-1.8.7-p334 :005 >
This is what my app/models/transaction_item.rb looks like:
class TransactionItem < ActiveRecord::Base
belongs_to :transaction
belongs_to :stylist
end
I blew away the TransactionItem table via a migration, then created a brand new migration to re-create it. That seems to have fixed the problem.