In my rails app, user's can create Designs.
Design.rb
belongs_to :user
User.rb
has_many :designs
I'm trying to create a new model Look so user's can create Looks. The way I envision this to work is when a user goes to /looks/new, they have a list of all the designs they have favorited (which I have that set up that variable already) in a table format with the right column being checkboxes where the user can go through and check a few of those Designs and click Create. All the Designs that have been checked would be part of that Look.
As I haven't done this sort of thing before, I need some help accomplishing this in all aspects MVC.
Look.rb
has_many :designs
Design.rb
belongs_to :looks # ??? Would the model be something different since technically when you create a design it doesn't belong to a look.
Looks Controller
def new
#designs = #user.favorites #This get's me all the designs that the particular user has favorited
#look = Look.new # ??? Again, as I haven't set this sort of relation up before, I'm unsure.
end
Please let me know any other code I can provide to help out. I may even be making this sound more complicated than it is.
This configuration should work for you Justin:
class User < ActiveRecord::Base
has_many :designs
has_many :looks, through: :designs
end
class Design < ActiveRecord::Base
belongs_to :user
has_many :designs_looks
has_many :looks, through: :designs_looks
end
class Look < ActiveRecord::Base
has_many :designs_looks
has_many :designs, through: :designs_looks
end
class DesignsLook < ActiveRecord::Base
belongs_to :design
belongs_to :look
validates :design_id, presence: true
validates :look_id, presence: true
end
I don't know what you want to do in the future but you might want to consider putting the user_id on the DesignsLook model, so you would not need a complex join query to retrieve all the Looks of a User. And also you implement shared Designs with all users
Your user has many designs. New looks can have many designs. And design can belong to MANY looks, users. Smells like has many ..., :through
http://guides.rubyonrails.org/association_basics.html#the-has-many-through-association
class User
has_many :designs, through: :design_possesion
end
class Look
has_many :designs, through: :look_designs
end
class Design
has_many :look_designs, :design_possesion
end
Of course you'll have to create corresponding tables.
Related
I have searched and searched and found only partial solutions to my current question.
The thing is, I'd like to know if it is possible to use has_many :through along with a polymorphic association in Ruby on Rails.
I have a system where students can create travel plans (that can belong to many students) and refund claims (that can belong to only one student) for their projects. In this system, both admin users and students are able to comment on the plans and claims.
My associations are:
class Student < ActiveRecord::Base
has_and_belongs_to_many :travel_plans
has_many :refund_claims
has_many :comments, through: :travel_plans
has_many :comments, through: :refund_claims
end
class AdminUser < ActiveRecord::Base
has_many :comments
end
class TravelPlan < ActiveRecord::Base
has_and_belongs_to_many :students
has_many :comments, as: :commentable
end
class RefundClaim < ActiveRecord::Base
belongs_to :student
has_many :comments, as: :commentable
end
class Comment < ActiveRecord::Base
belongs_to :commentable, polymorphic: true
end
My questions are:
Is it correct to associate comments twice in the Student model?
I don't want the AdminUsers to have travel plans and refund claims, how can I identify their comments as being made on a travel plan or on a refund claim?
Would there be a better approach?
Thanks a lot in advance for everyone!
Cheers,
You probably want to add an polymorphic author attribute to the Comment model. Than you just need has_many :comments, as: :author to the Student and AdminUser model.
If this is a new application and you are starting on the green field you might want to rethink your models a bit and add a Role and a User model. Student would than be a role of user as would AdminUser be.
Is it correct to associate comments twice in the Student model?
No, not really. If you have duplicate association name, you can only use one of them. If you want to use both, you have to name them differently.
I am trying to implement a resume feature and I was wondering the best practice for handling it. Lets assume a user has 2 pieces to a resume, education and work experience, and this is constant among all users. Then under each I want to save titles of things they've done (eg. Attended school at ______, worked at ________, project doing _______). Within these I want to save a description of that specific activity. What would be the best practice for implementing this?
So I need some association like: a user has_many experiences. An experience has_many titles. A title has_many descriptions. I also need to make the title of the experience is associated with the correct header (education or work experience).
I'm still pretty new to rails, and I'm sure there is a much easier and intuitive way to do this. Thanks for the help!
You can try these simple models structure for
class User < ActiveRecord::Base
has_many :locations
has_many :projects, through: experience_projects
end
class Location < ActiveRecord::Base
belongs_to :user
end
class Experience < ActiveRecord::Base
#experiences table should contain title and descriptions
belongs_to :user
has_many :projects, through: experience_projects
end
Now Join model if you do not require this intervention model you can directly use has_and_belongs_to_many
class ExperienceProject < ActiveRecord::Base
belongs_to :user
belongs_to :experience
end
I am curious how I would go about implementing this.
I am creating an online learning website. There are a few courses on this website that users can complete. Courses have complete attribute which is just a boolean.
I want each user's progress to be trackable. So let's say I am at the course show page and I want to be able to do
#course.complete?
and get a unique response for each user.
Right now I have a user model set up which can log in and out, but I do not have a relationship between users and courses.
What the best way to set up this relationship so that each course is unique to each user?
i.e. if User A has complete the course then it will show true. If User B has not completed the course then it will show false.
Thanks!
I would do it like this
class Student < ActiveRecord::Base
has_many :course_enrollments
has_many :courses, :through => :course_enrollments
# code here
end
class Course < ActiveRecord::Base
has_many :course_enrollments
has_many :students, :through => :course_enrollments
# code here
end
class CourseEnrollment < ActiveRecord::Base
belongs_to :student
belongs_to :course
# code here
end
I have a User model, which has_many Dish through Recommendation. I would like to enforce uniqueness of Dish, as well as uniqueness of Recommendation.
How should I go about this in ActiveRecord?
In my dish.rb:
validate_uniqueness_of :dish_name
What I would like to have is: when an user recommends a dish, create a new dish if it does not exist, then create recommendation. If the dish already exists, then just create recommendation and point to existing dish.
Do I need to handle these situations manually (i.e., checking existence of dish in controller), or ActiveRecord has a way to handle it internally?
Update:
validate_uniqueness_of :dish_name only checks and return error message if the dish was created there. It probably won't create new recommendation that points to existing dish.
You could always .find_or_create_by_<attribute> to find the dish to begin with
As I see, more than one user can recommend the same dish.
Your models should look like:
Class User < ActiveRecord::Base
has_many :recommendations
has_many :dishes, :through => :recommendations
end
Class Dish < ActiveRecord::Base
has_many :recommendations
has_many :users, :through => :recommendations
end
So your Recommendations table in database should have two columns (beside it's id and timestamps) called user_id and dish_id . To validate that a user doesn't recommend
the same dish twice, do:
Class Recommendations < ActiveRecord::Base
belongs_to :dish
belongs_to :user
validates_uniqueness_of :dish_id, :scope => :user_id
end
And i didn't know about the .find_or_create_by method that Dan recommended, so definetly try to use something like that.
Hope i helped :)
I'm in the process of trying to develop my first rails application and before I jump off into actually implementing my ideas, I was hoping I could get some help with my association planning.
My application is going to be an educational tool and I have some basic functionality that I need to implement. I want to have students that can register for and create courses. Within these courses, there will be one user who is the teacher and the rest are students. Within the course will be assignments that the teacher creates and that users are required to make a submission for. These are the basics. Eventually I want to add more functionality but as of now I just need the foundations set.
Here are my ideas so far on what the associations should look like:
class User < ActiveRecord::Base
has_many :enrollments
has_many :courses, :through => :enrollments
end
class Course < ActiveRecord::Base
has_many :enrollments
has_many :users, :through => :enrollments
end
class Enrollment < ActiveRecord::Base
belongs_to :user # foreign key - user_id
belongs_to :course # foreign key - course_id
end
However, I'm running into my wall of inexperience at the moment with how to appropriately handle the rest of the associations at this point. I could probably hack out something, but I'd prefer to do it as best as I can the first time.
How do I handle the associations related to assignments and submissions? Presumably a student's submission should belong_to them, but it is also specifically related to an assignment within the class. Assignments originate within a course, but are also closely tied to the user.
Finally, what's the best way to handle the relationships between a user and the class they create? A user creates a course. Does that course belong_to them? Should I just add a column to the course's table for storing the creator's id? Etc.
Thanks for the help.
Suggestion:
You might want to separate out your Teacher and Student models, since you're very likely to have different actions associated with each (and while they share some attributes, they really are different entities in your model, for example, you likely want just one teacher teaching in a course.)
You could derive both the Teacher model and the Student model from a User model that has the shared attributes and authentication.
Now to your questions:
If you'd like to keep the student that created the course associated, creator_id is the way I'd go. (If a teacher can create a course too, deriving Student and Teacher from a shared User model would help)
Assignments and Submissions:
You've pretty much defined it in words. Here is the code.
[If different students within a course could get different assignments, only then do you want to build a direct association between Student and Assignment, otherwise, use a through association]
class User < ActiveRecord::Base
has_many :enrollments
has_many :courses, :through => :enrollments
has_many :assignments, :through => :courses
has_many :submissions
end
class Course < ActiveRecord::Base
has_many :enrollments
has_many :users, :through => :enrollments
has_many :assignments
end
class Enrollment < ActiveRecord::Base
belongs_to :user # foreign key - user_id
belongs_to :course # foreign key - course_id
end
class Assignment < ActiveRecord::Base
belongs_to :course
has_many :submissions
end
class Submission < ActiveRecord::Base
belongs_to :assignment
belongs_to :user
end