I need to assign students (users) to classes (studentclasses)
I have a simple many-to-many relationship using 3 tables:
studentclasses (lesson details)
users (user... student info)
studentclass_users (Join table containing user_id and studentclass_id)
I'm using has_many :through and my models look like the following:
studentclass.rb
class Studentclass < ActiveRecord::Base
has_many :studentclass_users
has_many :users, :through => :studentclass_users
end
user.rb
class User < ActiveRecord::Base
...more here...
has_many :studentclass_users
has_many :studentclasses, :through => :studentclass_users
end
studentclass_users.rb
class StudentclassUsers < ActiveRecord::Base
belongs_to :studentclass
belongs_to :user
end
For testing purposes, I'm just using a hidden field in my studentclass new view partial to tack on a user id when creating the class and it is as follows:
_new.html.erb
<%= hidden_field_tag "studentclass[user_ids][]", 29%>
And in my studentclass controller:
studentclasses_controller.rb
def new
#studentclass = Studentclass.new
end
def create
#studentclass = Studentclass.new(params[:studentclass])
#studentclass.save!
end
My params comes back:
Parameters: {"utf8"=>"✓", "authenticity_token"=>"MjBTf4rtcyo8inADrSxPZB3vLOKtlZRVFlQJJzfCqWs=", "studentclass"=>{"class_title"=>"hjhkj", "user_ids"=>["29"]}, "commit"=>"Save"}
which seems fine but I get the following error:
NameError (uninitialized constant ActiveRecord::HasManyThroughSourceAssociationMacroError):
I think this is something simple with naming maybe? Any help would be appreciated
Related
I am trying to make an application using Rails 3.2.14, but I can't wrap my head around the model associations that I have built so far. I have four models which are interconnected to give desired result but so far it hasn't been working.
Job with fields: user_id, title
Jobapplication with fields: job_id, user_id, isrefused
Resume with fields: user_id, profession
I am trying to extract all the jobs which a particular user has applied for using the jobapplication model in an instance variable for the view.
All tables containing foreign keys have belong_to associations along with has_many at the other end.
So far, I have tried like this in the controller:
def applied job
#jobapplications = Jobapplication.where('user_id = ?', current_user.id)
#jobs = #jobapplications.jobs
end
The purpose is to find jobs for which the user has put in application for.
Should I redesign the models association?
The accessors can be greatly simplified if you write your model associations like this:
class User < ActiveRecord::Base
has_many :jobs # jobs posted
has_many :job_applications # job applications posted
has_many :applied_jobs, through => :job_applications, :source => :job # jobs applied for
has_one :resume
end
class Job < ActiveRecord::Base
belongs_to :user
has_many :job_applications
has_many :applicants, :through => :job_applications, :source => :user # applicants for this job
has_many :applicant_resumes, :through => :job_applications, :source => :resume
end
class JobApplication < ActiveRecord::Base
belongs_to :user
belongs_to :job
has_one :resume, :through => :user # the resume for the application
end
class Resume < ActiveRecord::Base
belongs_to :user
end
Now you can easily find the jobs a user applied for:
current_user.applied_jobs
Or all the applicants (users applying) for a specific job:
#job.applicants
And you can see a user's resume:
current_user.resume
Or an application's resume:
#job_application.resume
Or all resumes for those applying for a specific job:
#job.applicant_resumes
This looks okay:
#jobapplications = Jobapplication.where("user_id =?", current_user.id)
but not sure about this:
#jobs = #jobapplications.jobs
What's the jobs method?
try this:
#some_controller.rb
def applied_job #note the underscore!
#jobapplications = Jobapplication.where("user_id =?", current_user.id)
end
and in the view
<% #jobapplications.each do |application| %>
#list applications here
<% end %>
I have the following models associations which I want to use in order to do some searches of players:
class Player < ActiveRecord::Base
belongs_to :user
has_many :abilities
has_many :sports, :through => :abilities
...
end
class User < ActiveRecord::Base
has_one :player
...
end
class Ability < ActiveRecord::Base
belongs_to :player
belongs_to :sport
has_one :level
...
end
class Sport < ActiveRecord::Base
has_and_belongs_to_many :category_sports
has_many :abilities
has_many :players, :through => :abilities
...
end
class CategorySport < ActiveRecord::Base
has_and_belongs_to_many :sports
end
I have a form where a user can fill two inputs: city and sport
The city field is in the User model as (#user.city) and the sport field can be either in CategorySport as (#category_sport.name) or in the Sport model as (#sport.name).
Right now I have the following to perform the search in the Player model:
def search
self.find(:all,:include => 'user',:conditions => ['users.city LIKE ?', "%#{city}%"])
end
I would like to know how would I add the join model (ability) and related (sport, categorysport) in this query in order to find by sport too. So, not just find for user city but also by sport.
Try this:
def search
self.includes(:user, :abilities => {:sport => :category_sports}).
where(['users.city LIKE ? OR category_sports.name=? OR sports.name=?',
"%#{city}%", sport, sport])
end
So if I have the following relationship
class Item < ActiveRecord::Base
has_many :item_user_relationships
has_many :users, :through => :item_user_relationships
end
class User < ActiveRecord::Base
has_many :item_user_relationships
has_many :items, :through => :item_user_relationships
end
class ItemUserRelationship < ActiveRecord::Base
belongs_to :item
belongs_to :user
attr_accessible :role
end
What's the rails way to include the role attribute when listing all the Users of an Item?
#users = #item.users # I want to include the role as part of a user
Thanks!
UPDATE: I'm still having trouble with this. My goal is to get an array of User models that have their role included in the attributes.
I'm note sure if I understand you correctly, but maybe this is what you want?
#users = #item.users
#users.each do |user|
puts user.item_user_relationships.first.role
end
I've built a simple Friend model, which allows Users to have multiple friends. Here's what that looks like:
class Friend < ActiveRecord::Base
belongs_to :user
class User < ActiveRecord::Base
has_many :friends
Each friend record just has an id, user_id and friend_id. The user_id is the id of the user it belongs to and the friend_id is the id of user they are befriending.
Here's my problem
I'm not quite sure how to display a list of a particular user's friends. #user.friends will give me a list of all the friend records they have, but not the user accounts of those friends.
For instance, I am trying to build a show page for the friends controller:
class FriendsController < ApplicationController
def show
#user = current_user
end
SHOW.HTML.ERB
<% if #user.friends.count > 0 %>
<% #user.friends.each do |friend| %>
<div class="entry">
<%= friend.username %>
This does not work because friend in this case does not have username. I need to do something like this in my controller:
#friend = User.find_by_id(friend.friend_id)
But I'm not sure how I would call that in my view in the #user.friends loop. Any thoughts appreciated. Let me know if I need to be more clear.
UPDATE
I've updated my User model like so:
has_many :friends, :include => :user
has_many :friended_users, :through => :friends, :source => :user, :uniq => true
However, when I run #user.friended_users it's giving me the user_ids (which is the same as #user) rather than friend_ids.
How can I tweak that relationship so it's linking to the friend_id rather than user_id?
The more I think about it, I think I may not have set up the relationship properly in the first place. Maybe a User should has_many :users, through => 'friends', but that doesn't really make sense...
UPDATE
I've updated my models based on #twooface's input:
class User < ActiveRecord::Base
has_many :friendships
has_many :friends, :through => :friendships
class Friendship < ActiveRecord::Base
belongs_to :user
belongs_to :friend, :class_name => 'User'
class Friend < ActiveRecord::Base
has_many :friendships
has_many :users
I'm just not sure what my Friends table should look like. I assume it should have a primary key and a user_id? If I create a friendship and friend record, I can do friendship.user and friendship.friend and get the correct results, but user.friends gives me an empty hash...
I think your relations are built a bit wrong. Try something like this:
class User < ActiveRecord::Base
has_many :friends
has_many :friendships
has_many :friends, :through => :friendships
class Friendship < ActiveRecord::Base
belongs_to :user
belongs_to :friend, :class_name => 'User'
# This class has :user_id and :friend_id
Then everything will be simpler. Every user will have an array of friends that will be just users.
User.first.friends
Will return an array of Users that this User friends.
Hope this helps.
Hi im quite beginner in rails. i have a problem suggestion will be appreciated.
i have two model "user" and "asset"
an "asset" is created by a "user" and asset" can be assigned to a "user" schema is
Asset { id,name,creator_id,assigned_to_id,price,...}
User{ id,name,....}
now in Asset model class association are
class Asset < ActiveRecord::Base
{
#validation
belongs_to :creator ,:class_name=>'User'
belongs_to :assigned_to, :class_name=>'User' ,:foreign_key=>'assigned_to_id'
}
and User Model is
class User < ActiveRecord::Base
{
#any validation and other stuff
has_many :assets #did not specify either this association is for creator , or assigned_to user.how can is specify that??
}
now in Asset show view i can obtain creator name with
#asset.creator.name
but can't assigned_to name
#asset.assigned_to.name =>(error is )undefined method `first_name' for nil:NilClas
and
#asset.assigned_to_id.name=>(error is) undefined method `first_name' for 1:Fixnum
any suggestion how can i make double association with same model
ok solution was in my last comment.
Multiple relation with same model
class Asset < ActiveRecord::Base
belongs_to :creator ,:class_name=>'User'
belongs_to :assigned_to, :class_name=>'User'
end
user.rb
class User < ActiveRecord::Base
has_many :created_assets, :foreign_key => 'creator_id', :class_name => 'Asset'
has_many :assigned_assets , :foreign_key => 'assigned_to_id', :class_name => 'Asset'
end