I have 2 models: User and PrivateMessage which must be associated (as user has many private messages as reciever and sender, private messages belongs to user)
It's my private_messages table structure:
private_messages:
sender_id:integer
reciever_id:integer
title:string
message:text
It's hard for me to understand how can I connect same message for both sender user and reciever user, now my models code looks like:
class User < ActiveRecord:Base
has_many :private_messages
end
and
class PrivateMessage < ActiveRecord::Base
belongs_to :user, :through => :sender_id
belongs_to :user, :through => :reciever_id
end
Is that correct?
You have to rename your associations to tell them apart:
class PrivateMessage < ActiveRecord::Base
belongs_to :sender, :class_name => 'User', :foreign_key => 'sender_id'
belongs_to :receiver, :class_name => 'User', :foreign_key => 'receiver_id'
end
class User < ActiveRecord::Base
has_many :sent_messages, :class_name => 'PrivateMessage', :foreign_key => 'sender_id', :dependent => :destroy
has_many :received_messages, :class_name => 'PrivateMessage', :foreign_key => 'receiver_id', :dependent => :destroy
end
Related
I'm currently modeling a Rails 3.2 app and I need a polymorphic association named "archivable" in a table named "archives". No worries with it, but my "archives" table must also belongs_to a "connections" table. I just want to know if there's any constraints from Rails to do that.
You can see the model here
Another detail, my Connection model has twice user_id as foreign key. A user_id as sender and a user_is as receiver. Possible? I think what I did below won't work...
Here are my models associations.
class User < ActiveRecord::Base
has_many :connections, :foreign_key => :sender
has_many :connections, :foreign_key => :receiver
end
class Connections < ActiveRecord::Base
belongs_to :user
has_many :archives
end
class Archive < ActiveRecord::Base
belongs_to :connection
belongs_to :archivable, :polymorphic => true
end
class Wink < ActiveRecord::Base
has_many :archives, :as => :archivable
end
class Game < ActiveRecord::Base
has_many :archives, :as => :archivable
end
class Message < ActiveRecord::Base
has_many :archives, :as => :archivable
end
Do you see anything wrong or something not doable with Rails?
Thank you guys.
I think you want to do this :
class Connections
belongs_to :sender, :class_name => 'User', :foreign_key => 'sender_id'
belongs_to :receiver, :class_name => 'User', :foreign_key => 'receiver_id'
end
class User
has_many :sended_connections, :class_name => 'Connection', :as => :sender
has_many :received_connections, :class_name => 'Connection', :as => :receiver
end
Important : Don't declare 2 times has_many :connections with the same name !
class Person
has_many :owned_groups, :class_name => "Group", :foreign_key => :owner_id
has_many :owned_group_memberships, :through => :owned_groups,
:source => :group_memberships
has_many :group_memberships, :foreign_key => "member_id"
has_many :groups, :through => :group_memberships
end
class GroupMembership
belongs_to :member, :class_name => 'Person'
belongs_to :group
end
class Group
belongs_to :owner, :class_name => "Person"
has_many :group_memberships
has_many :members, :through => :group_memberships
end
I want to create the model Message so a Person can post a new message in the group#show page. But for that she/he must be from the Group in question, or the owner, or have a group_membership (be a member) from this group.
How would be the associations of the model Message?
class Message < ActiveRecord::Base
belongs_to :person
belongs_to :group
validate :has_group_permission
def has_group_permission
unless self.person.owned_groups.include?(self.group) || self.person.groups.include?(self.group)
self.errors.add(:base, "you don't have permission to add a message to this group."
end
end
end
The situation is this way..
class Organization < ActiveRecord::Base
has_many :role_memberships
has_many :roles
has_many :users, :through => :role_memberships, :uniq => true
end
class User
has_many :role_memberships
has_many :organizations, :through => :role_memberships, :uniq => true
has_many :roles, :through => :role_memberships, :uniq => true
end
class RoleMembership < ActiveRecord::Base
belongs_to :organization
belongs_to :role
belongs_to :user
end
class Role < ActiveRecord::Base
belongs_to :organization
has_many :role_memberships
has_many :users, :through => :role_memberships, :uniq => true
end
The QUESTION is how do I populate all the three foreign-keys in rolemembership table..when I do org.users.push(u) this create a record but role_id is left out...
In this case I will probably create RoleMembership object itself, like this:
RoleMembership.create(:organization_id => org.id, :role_id => role.id, :user_id => user.id)
Quick question (I think). I have users, and I would like to allow them to send messages to one another. My question is, should I have a user table, a message table, and a users to messages join table, or should I just store to_user_id and from_user_id in the messages table. If the latter, what would the association look like for that? Can you even reference a 'local' key for an association?
You can do that with a couple of simple has_many associations. Since it's self-referential, you'll need to override some of the Rails magic to make it work.
class User < ActiveRecord::Base
has_many :sent_messages, :class_name => 'Message', :foreign_key => 'sender_id'
has_many :received_messages, :class_name => 'Message', :foreign_key => 'recipient_id'
end
class Message < ActiveRecord::Base
belongs_to :sender, :class_name => 'User'
belongs_to :recipient, :class_name => 'User'
end
Rails doesn't have a cleaner way to doing self-referential associations that I know of.
I think the latter sounds fine. This is just off the top of my head but I know AR's associations have options like this...
class Message < ActiveRecord::Base
belongs_to :sender, :class_name => :user, :foreign_key => :from_user_id
belongs_to :recipient, :class_name => :user, :foreign_key => :to_user_id
#...
end
class User < ActiveRecord::Base
has_many :received_messages, :class_name => :message, :foreign_key => :to_user_id
has_many :sent_messages, :class_name => :message, :foreign_key => :from_user_id
end
I have two classes Message and User. Message has sender_id and recipient_id both foreign keys for User. How to build relationship where I'll be able to get user for both sender and recipient, like #message.sender.name and #message.recipient.name
I tried to do it by this way:
class Message < ActiveRecord::Base
belongs_to :sender, :class_name => 'User', :foreign_key => 'sender'
belongs_to :recipient, :class_name => 'User', :foreign_key => 'recipient'
end
class User < ActiveRecord::Base
has_many :recivied_messages, :class_name => 'Message', :foreign_key => 'recipient'
has_many :send_messages, :class_name => 'Message', :foreign_key => 'sender'
end
But it didn't help, when I'm trying to access to, for instance, #message.recipient.name it says that "undefined method `name'"
You can use the :class_name property to set which class gets used for a foreign key:
class Message < ActiveRecord::Base
has_one :sender, :class_name => User
has_one :recipient, :class_name => User
end
class User < ActiveRecord::Base
belongs_to :sent_messages, :class_name => Message
belongs_to :received_messages, :class_name => Message
end
Also, you say you are using sender_id and recipient_id for the foreign keys, but in your code you have :foreign_key => 'sender' and :foreign_key => 'recipient'. Have you tried changing them to :foreign_key => 'sender_id' and :foreign_key => 'recipient_id'? So:
class Message < ActiveRecord::Base
has_one :sender, :class_name => User, :foreign_key => 'sender_id'
has_one :recipient, :class_name => User, :foreign_key => 'recipient_id'
end
class User < ActiveRecord::Base
belongs_to :sent_messages, :class_name => Message, # ...etc
belongs_to :received_messages, :class_name => Message, # ...etc
end