Help re: self-referencing models

ruby-talk
1

All,

I'm still working my way around learning Rails and I'm not having much luck finding the relevant answers I need; that said, I suspect it's something that's been done before since I've done this by hand many times in the past myself.

I have a table called tab_accounts with account_id(int) as PK. I also have a lookup table called mtom_account_relations. This table has two int columns (account_subject, account_associate), both of which are FK to tab_accounts.account_id. The purpose of this layout is to allow for a many-to-many relationship between tab_account entries. The goal is to create an endpoint that returns an account's details along with a list of its associates, also accounts.

At this point I have the following:

models/account_relation.rb:

class AccountRelation <ApplicationRecord self.table_name ="mtom_account_relations" belongs_to :subject,foreign_key:"account_id",class_name:"Account" belongs_to :associate,foreign_key:"account_id",class_name:"Account" end

models/account.rb

class Account <ApplicationRecord self.table_name ="tab_accounts" self.primary_key ="account_id" ...
   has_many:account_relations has_many :associates,:through => :account_relations has_many :subjects,:through => :account_relations end

controllers/account_controller.rb

class AccountsController <ApplicationController ...
   def associates _account_id = params[:account_id]
     @rs_account =Account .select("tab_accounts.account_id, tab_accounts.screen_name, tab_accounts.friends, tab_accounts.followers")
                       .where(:tab_accounts => {account_id:_account_id})
                       .as_json[0]
     @rs_account['associates'] =Account.select("tab_accounts.account_id, tab_accounts.screen_name")
                                       .joins(:subjects)
                                       .where(:tab_accounts => {account_id:_account_id})
                                       .as_json
     render json:@rs_account end end

config/routes.rb:

Rails.application.routes.drawdo ...
   get 'accounts/associates/:account_id',:to => "accounts#associates" end

When I run the method I get the following error:

PG::UndefinedColumn: ERROR: column mtom_account_relations.account_id does not exist LINE 1: ..._accounts" INNER JOIN "mtom_account_relations" ON "mtom_acco... ^ : SELECT tab_accounts.account_id, tab_accounts.screen_name FROM "tab_accounts" INNER JOIN "mtom_account_relations" ON "mtom_account_relations"."account_id" = "tab_accounts"."account_id" INNER JOIN "tab_accounts" "subjects_tab_accounts" ON "subjects_tab_accounts"."account_id" = "mtom_account_relations"."account_id" WHERE "tab_accounts"."account_id" = $1

1. I suspect the call to the non-existent table "subjects_tab_accounts" is being created from my .joins(:subjects) clause in the controller.

2. It thinks there's a "mtom_account_relations"."account_id" column.

I'd be grateful for any actionable assistance. Thank you for your attention.

  - Joe

···

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

2

Is it not that you need to specify the foreign_key and class_name options
for your has_many through relations?

Something like:

  has_many :associates, :through => :account_relations, foreign_key:
'account_associate', class_name: 'Account' has_many :subjects,
:through => :account_relations, foreign_key: 'account_subject',
class_name: 'Account'

I could be barking up the wrong tree though, check out the association
reference here:
http://guides.rubyonrails.org/association_basics.html#has-many-association-reference

Particularly have a look at section 4.3.2 which details the options for has_many

Cheers,

Rhys