Starting with Companies. Each company has many users. Each user can
have one or more submissions (of articles related to a company). Hence
each submission needs to be linked to a company. Up to this stage, I
could probably use :through to link submissions to Companies. So far
so good.
But the complication comes in as such: Each user can make a submission
related not only to the company he belongs to but also to other
companies available on record. In which case the :through option may
not work any more in this scenario, I think.
I have been thinking about this for days and due to my limited
knowledge of relationships, I couldn't come up with a feasible
solution. So far I came up with the following relationships:
class Company < ActiveRecord::Base
has_many :users
has_many :submissions
end
class User < ActiveRecord::Base
belongs_to :company
has_many :submisions
end
class Submission < ActiveRecord::Base
belongs_to :company
belongs_to :user
end
I have a suspicion that this setup will not work. The more I think
about it, the more confused I become. If someone could help with some
inputs/advice as how to go about this, it will be greatly appreciated.
Thanks Ryan for your input.
I thought over you have suggested, and I think it doesn't quite work
for the case that I have.
Let me try to explain my scenario again.
I have a table of companies. Each company has multiple users.
Each user can submit one or more articles.
Each article is about a company (that exists in the company table) and
that company may or may not be the same company that the user
(submitting the article) belongs to.
For example.
I have a User1 who belongs to Company A. He creates an article
submission about Company B.
How do I link the submission to Company B, since the article is about
company B?. Using the has_many :through => users as you have
suggested, I believe it will link the submission to Company A instead.
Maybe the model I am using to approach the problem may not be correct.
I am open to learning a better approach to this type of scenario.
Off top, I'm thinking you want to keep your 1:M relationships between
companies and users, and between users and submissions, but go M:M on
the one between companies & submissions. IOW, make the relationship
between submissions & companies independent of the user. So something
like:
class User < ar::base
belongs_to :company
has_many :submissions
end
class CompaniesSubmissions < ar::base
belongs_to :company
belongs_to :submission
end
class Submission < ar::base
belongs_to :user
has_many :companies_submissions
has_many :companies, :through => :companies_submissions
end
class Company < ar::base
has_many :users
has_many :companies_submissions
has_many :submissions, :through => :companies_submissions
end
You'll probably at least want to default the addition of the submitting
user's company to Submission.companies (if not actually enforce that as
a validation requirement.) Not sure what the most graceful way to do
that would be...
Thanks Ryan for your input.
I thought over you have suggested, and I think it doesn't quite work
for the case that I have.
Let me try to explain my scenario again.
I have a table of companies.
OK
class Company < ActiveRecord::Base
end
Each company has multiple users.
class Company < ActiveRecord::Base
has_many :users
end
class User < ActiveRecord::Base
belong_to :company
end
Each user can submit one or more articles.
class Article < ActiveRecord::Base
belongs_to :user
end
class Company < ActiveRecord::Base
has_many :users
end
class User < ActiveRecord::Base
belong_to :company
has_many :articles
end
Each article is about a company (that exists in the company table) and
that company may or may not be the same company that the user
(submitting the article) belongs to.
class Article < ActiveRecord::Base
belongs_to :user
belongs_to :company
end
class Company < ActiveRecord::Base
has_many :users
has_many :articles
end
class User < ActiveRecord::Base
belong_to :company
has_many :articles
end
I am not sure you need :through relationships at all.
You don’t need the through relationships. It wasn’t clear to me originally what he wanted, so I assumed he wanted to see what submissions were made by the users of a company, and has_many :through came to mind.
You don't need the through relationships. It wasn't clear to me
originally
what he wanted, so I assumed he wanted to see what submissions were made
by
the users of a company, and has_many :through came to mind.
Andrew's solution seems to fit the bill, I think.
What's more - it's exactly what maestro777 started with.
I suspect he might be having problems getting the results he wants using
this structure.
I'm glad to find out that I was on the right track after all from the
beginning, with my models set up. It wasn't that I was having problem
getting the result I wanted. Rather the source of my confusion came
from a misunderstanding on what I was reading in one of the ROR books
about model relationship. Now that you confirmed I was on the right
track, I went back to read the same passage again and realized that it
was talking about a different kind of relationship, than what I had in
mind.
One user (who coincidentally happens to belong to a company) writes an
article about zero or more companies. You will need, in addition to
users, submissions, and companies, a new table (and model) that has
all three ids: user_id, submission_id, and company_id.
Or, since a submission is the product of only one user, you put user_id in submissions, and then do a many:many between submissions and companies (so you have a submissions_companies join table w/submission_id and company_id).
