Self referential has many through - belong to association dows not work ???

rubyonrails-talk
1

I'm trying to set up a self-referential relationship, as described in this great video - #163 Self-Referential Association - RailsCasts - and it's mostly working, but not entirely.

My self-referential relationship describes relationships between people using the foreign keys person and related_person in class Relationship both associating to the class Person

My problem is that when I update related_person_id for a specific relationship the associated object relationship.related_person is not updated. Related_person_id in relationship has an updated value, while relationship.related_person.id has the old value. What is wrong in my declarations ?? They are as follows

Class Person

has_many :relationships, :dependent=>:destroy, :autosave=>true   has_many :people, :through => :relationships, :source=>:person, :uniq=>true   has_many :related_people, :through => :relationships, :source=>:related_person, :uniq=>true

Class Relationship   belongs_to :person   belongs_to :related_person, :class_name => 'Person',:foreign_key =>'related_person_id'

Table relationships class CreateRelationships < ActiveRecord::Migration   def self.up     create_table :relationships do |t|       t.integer :person_id, :default=> nil       t.integer :related_person_id, :default=> nil       t.string :person_role, :limit=>80       t.string :related_person_role, :limit=>80       t.integer :family_id, :default=> nil       t.integer :event_id, :default=> nil       t.integer :user_id, :default=> nil       t.integer :archive_id, :default=> nil       t.timestamps     end     add_index :relationships, :person_id     add_index :relationships, :related_person_id     add_index :relationships, :archive_id     add_index :relationships, :person_role, :index => true     add_index :relationships, :related_person_role, :index => true   end

2

Hans <Hans.Marmolin@...> writes:

I'm trying to set up a self-referential relationship, as described in this great video - #163 Self-Referential Association - RailsCasts

association

- and it's mostly working, but not entirely.

My self-referential relationship describes relationships between people using the foreign keys person and related_person in class Relationship both associating to the class Person

My problem is that when I update related_person_id for a specific relationship the associated object relationship.related_person is not updated. Related_person_id in relationship has an updated value, while relationship.related_person.id has the old value. What is wrong in my declarations ?? They are as follows

Class Person

has_many :relationships, :dependent=>:destroy, :autosave=>true   has_many :people, :through => :relationships, :source=>:person, :uniq=>true   has_many :related_people, :through => :relationships, :source=>:related_person, :uniq=>true

Class Relationship   belongs_to :person   belongs_to :related_person, :class_name => 'Person',:foreign_key =>'related_person_id'

The code looks OK to me. Are you sure it's not a caching/stale record problem? Fire up a console and execute your code manually. If you see the same error try reloading the instance, eg:

person.reload

This will ensure you are looking at a current version from the database rather than a (possibly) stale version in Ruby memory.

3

Nothing, but updating the related_person_id field is the problem. You'll typically want to update the relationship with an object (assigning to related_person).

--Matt Jones

4

Thanks for the advices

Matt do you mean that I should use relationship.related_person=Person.new instead of changing the foreign key directly If so, is that a general requirement when updating foreign keys ?

Andrew How do I avoid the caching/stale record process I have tried to make an extra save for all involved object but did not change anything

5

Hans <Hans.Marmolin@...> writes:

Thanks for the advices

Matt do you mean that I should use relationship.related_person=Person.new instead of changing the foreign key directly If so, is that a general requirement when updating foreign keys ?

I think he means:

person = Person.first other_person = Person.last person.relationships << other_person

or

person.relationships << Person.new

or even better

person.relationships << Person.create(params[:person])

Andrew How do I avoid the caching/stale record process I have tried to make an extra save for all involved object but did not change anything

Stale objects can be a fickle affair and there are no magic bullets. Sorry.