I have a nested model like so:
class Games::Player < ActiveRecord::Base
attr_accessible :user_id
belongs_to :user
has_many :games_extras_achievements_players, :class_name => 'Games::Extras::AchievementsPlayer'
has_many :games_extras_achievements, :class_name => 'Games::Extras::Achievement',:through=>:games_extras_achievements_players
validates :user_id,uniqueness: true
end
class Games::Extras::Achievement < ActiveRecord::Base
has_many :games_extras_achievements_players, :class_name => 'Games::Extras::AchievementsPlayer'
has_many :games_players, through: :games_extras_achievements_players, class_name: 'Games::Player'
end
class Games::Extras::AchievementsPlayer < ActiveRecord::Base
attr_accessible :games_extras_achievement_id, :games_player_id
belongs_to :games_extras_achievement, :class_name => 'Games::Extras::Achievement'
belongs_to :games_player, :class_name => 'Games::Player'
end
Objects on the join class work as expected.
However trying to get player -> achievement or vice versa gives an error:
> p.games_extras_achievements
Games::Extras::Achievement Load (0.3ms) SELECT "games_extras_achievements".* FROM "games_extras_achievements" INNER JOIN "games_extras_achievements_players" ON "games_extras_achievements"."id" = "games_extras_achievements_players"."games_extras_achievement_id" WHERE "games_extras_achievements_players"."player_id" = 1
ActiveRecord::StatementInvalid: PG::UndefinedColumn: ERROR: column games_extras_achievements_players.player_id does not exist
LINE 1: ...ents_players"."games_extras_achievement_id" WHERE "games_ext...
If I change the migration to use player_id like it is trying to find, I get an error stating that games_player_id does not exist
I seem to have fixed it.
I needed to use the non-namespaced column names and add a foreign key constraint.
class Games::Player < ActiveRecord::Base
attr_accessible :user_id
belongs_to :user
has_many :games_extras_achievements_players, :class_name => 'Games::Extras::AchievementsPlayer'
has_many :games_extras_achievements, :class_name => 'Games::Extras::Achievement',:through=>:games_extras_achievements_players
validates :user_id,uniqueness: true
end
class Games::Extras::Achievement < ActiveRecord::Base
has_many :games_extras_achievements_players, :class_name => 'Games::Extras::AchievementsPlayer'
has_many :games_players, through: :games_extras_achievements_players, class_name: 'Games::Player'
end
class Games::Extras::AchievementsPlayer < ActiveRecord::Base
attr_accessible :achievement_id, :player_id
belongs_to :games_extras_achievement, class_name:'Games::Extras::Achievement',foreign_key: :achievement_id
belongs_to :games_player, class_name: 'Games::Player',foreign_key: :player_id
end
Hopefully this will save someone some aggravation.
Related
I just upgraded to Rails 3.2.10 and am getting an error message that I never used to get when updating a record via RailsAdmin.
ActiveRecord::HasManyThroughNestedAssociationsAreReadonly at /admin/vendor/12/edit
Message Cannot modify association 'Vendor#categories' because it goes through more than one other association.
This is my Vendor model:
class Vendor < ActiveRecord::Base
attr_accessible :name, :description, :banner_image, :logo_image, :intro_text, :thumb_image, :category_ids, :product_ids, :user_id, :remove_banner_image, :banner_image_cache, :remove_logo_image, :logo_image_cache
mount_uploader :banner_image, ImageUploader
mount_uploader :logo_image, ImageUploader
mount_uploader :thumb_image, ImageUploader
has_many :products, :dependent => :destroy
has_many :categories, :through => :products
belongs_to :owner, :class_name => "User",
:foreign_key => "user_id"
end
This is my Category model:
class Category < ActiveRecord::Base
attr_accessible :name, :product_ids, :category_ids
has_many :category_products do
def with_products
includes(:product)
end
end
has_many :products, :through => :category_products
end
This is my Product model:
class Product < ActiveRecord::Base
attr_accessible :name, :description, :price, :vendor_id, :image, :category_ids, :sku, :remove_image, :image_cache
mount_uploader :image, ImageUploader
belongs_to :vendor
has_many :category_products do
def with_categories
includes(:category)
end
end
has_many :categories, :through => :category_products
end
This is my CategoryProduct model:
class CategoryProduct < ActiveRecord::Base
attr_accessible :product_id, :category_id, :purchases_count
belongs_to :product
belongs_to :category
validates_uniqueness_of :product_id, :scope => :category_id
end
This happens because your association is nested, meaning (from rails source) :
A through association is nested if there would be more than one join table... which is your case here.
Apparently a workaround (I didn't test) is telling Vendor it doesn’t need to autosave the association.
has_many :categories, :through => :products, :autosave => false
You can mark the association as readonly and rails_admin will then not generate the category fields in the form for vendor:
has_many :categories, -> { readonly }, through: :products
I have a has_many through relationship between Course and User.
class Course < ActiveRecord::Base
belongs_to :user
has_many :enrollments, :dependent => :delete_all
has_many :users, :through => :enrollments
attr_accessible :description, :duration, :name, :prerequisites, :short_name, :start_date, :user_id
accepts_nested_attributes_for :users, :allow_destroy => true
attr_accessible :users_attributes
and User:
class User < ActiveRecord::Base
has_many :subjects, :class_name => "Course" # to get this call user.subjects
has_many :enrollments, :dependent => :delete_all
has_many :courses, :through => :enrollments
and Enrollment:
class Enrollment < ActiveRecord::Base
belongs_to :course
belongs_to :user
attr_accessible :course_id, :user_id
end
Now I'm trying to set user_ids from inside Course, using a nested form. It keeps giving me that Mass Assignment warning, and nothing is saved. I read I was supposed to add attr_accessible user_id but it still doesn't work.
Even if I do something like this from the rails console:
#c.update_attributes({:user_ids => [7,8]})
with #c being the course
Any help would be greatly appreciated,
Thank you.
It's user_ids, not user_id.
You need to add user_ids to your attr_accessible.
Is it possible to make a has_one relationship work like this?
I would like to be able able to load records like this:
#person = Person.find(1) => {Person id: 1, favorite_house_id: 10}
#person.favorite_house => {House id: 10....)
class Person < ActiveRecord::Base
has_many :houses, through: :person_houses
has_one :favorite_house, through: :person_houses
end
class PersonHouse < ActiveRecord::Base
belongs_to :house
belongs_to :person
end
class House < ActiveRecord::Base
has_many :people, through: :person_houses
end
Replace the has_one relation of Person by:
belongs_to :favorite_house, :class_name => "House"
Do not forget to create a column favorite_house_id in the table of Person.
Warning:Total Rails Newb (TRN). This should be a pretty basic question so I'm hoping someone can spare a couple mins to help shed some light.
Let's say I have the following models: User, Group, and Member
A user can have many groups (let's say friends, family, etc)
A group can have many members, namely other users.
How would I structure this?
Initially I tried this:
class User < ActiveRecord::Base
has_many :groups
has_many :groups, :through => :members
end
class Groups < ActiveRecord::Base
has_many :users, :through => :members
belongs_to :user
end
class Member < ActiveRecord::Base
belongs_to :group
belongs_to :user
end
However this gave me an error in User so I changed
has_many :groups, :through => :members
to
has_many :memberships, :through => :members, :source => :groups
Still getting an error about missing association when I try to do
group = Group.new
group.user.new
It will be useful: http://railscasts.com/episodes/47-two-many-to-many
class User < ActiveRecord::Base
has_many :members
has_many :groups, :through => :members
has_many :groups_as_owner, :class_name => "Group"
end
class Groups < ActiveRecord::Base
has_many :members
has_many :users, :through => :members
belongs_to :owner, :class_name => "User", :foreign_key => :user_id
end
class Member < ActiveRecord::Base
belongs_to :group
belongs_to :user
end
basically has_many-through associations are n:m associations (join-tables) that (shall) have more attributes than just the id's of the joined record ids...
so you have a table Groups (with an id), a table Users (with an id) and a table Members (no id, but user_id and group_id)
basically, what you did is nearly correct, just think about how you access a group from a user or vice versa....
a user would first look up its member information and through that member information get access to the group information ... and vice versa for a group
so you first set up
has_many :members
and then call
has_many :groups, :through => :members
all you need is
class User < ActiveRecord::Base
has_many :members
has_many :groups, :through => :members
end
class Groups < ActiveRecord::Base
has_many :members
has_many :users, :through => :members
end
class Member < ActiveRecord::Base
belongs_to :group
belongs_to :user
end
and you have another bug in your code above
you might want to use
user = group.users.new
instead of
user = group.user.new
Try this structure:
class User < ActiveRecord::Base
has_many :members
has_many :groups, :through => :members
end
class Groups < ActiveRecord::Base
has_many :members
has_many :users, :through => :members
end
class Member < ActiveRecord::Base
belongs_to :group
belongs_to :user
end
Also take a look at has_and_belongs_to_many, if you don't need to do with class Member then you should use has_and_belongs_to_many. In this case don't forget to create joining table in the database
I using rails3 and trying to build some complex associations.
I have Product, Version and Property models.
class Version < ActiveRecord::Base
belongs_to :product
has_many :specs
has_many :properties, :through => :specs
end
class Product < ActiveRecord::Base
has_many :versions
has_many :specs
has_many :properties, :through => :specs
end
class Property < ActiveRecord::Base
end
class Spec < ActiveRecord::Base
belongs_to :product
belongs_to :spec
belongs_to :version
end
It works perfect, but i want to use product and version as polymorphic relations, so table specs will have only spec_id and some_other_id, instead of spec_id, product_id, version_id.
I can't figure out where i should put :as and where :polymorphic => true. Can you help me?
How about:
class Version < ActiveRecord::Base
belongs_to :product
has_many :specs, :as => :speccable
has_many :properties, :through => :specs
end
class Product < ActiveRecord::Base
has_many :versions
has_many :specs, :as => :speccable
has_many :properties, :through => :specs
end
class Property < ActiveRecord::Base
end
class Spec < ActiveRecord::Base
belongs_to :speccable, :polymorphic => true
belongs_to :spec
end
#table: specs(id,spec_id,speccable_type,speccable_id)