Adding parent record to all tables

I want to add an "Organisations" table to a Rails app so that I can
separate all tables by organisation.

I have put 'organisation_id' on all tables but I need to work out the
best way to refactor the app to cope with the new relationships.

Any suggestions welcome especially if somebody has done something
similar.

Cheers
George

I think that a better way would be to create a separate database per
organization. Every organization could have their own subdomain. And
you could change the database connection during each request to the
proper database. Another way would be to extend every table primary
key with :organization_id. Of course to do that you would have to use
plugin that adds composite primary keys support to active record.

Depending on the application code, if it is not too complicated and
you always you AR queries (I mean, you do not genery by yourself sql
queries) you could make a solution like this:

#application controller

before_filter :find_organization
around_filter :within_organization

private

def find_organization
  @organization = Organization.find(session[:organization_id])
end

def within_organization
  ActiveRecord::Base.send(:with_scope, :find => where("organization_id
= ?", @organization.id")) do
    yield
  end
end

I am not sure whether it could works. Maybe you would have to do it
with every class instead...

def within_organization
  User.send(:with_scope, :find => where("organization_id = ?",
@organization.id")) do
    Article.send(:with_scope, :find => where("organization_id = ?",
@organization.id")) do
      Comment.send(:with_scope, :find => where("organization_id = ?",
@organization.id")) do
        yield
      end
    end
  end
end

Robert Pankowecki

Thanks for the ideas Rupert,

I have not really done much with filters so I might think about that.
Not sure If I understand entirely what you are trying to do though.

The queries are not too much of a problem as I can inject an
organisation_id into them and I have covered off the relationships by
creating a super class for all the tables with a
"belongs_to :organisation"

The bigger problem is to ensure that all the tables get the
organisation_id set on create. I tried to set the organisation_id in
an Activerecord callback in the superclass of all the models but I
cant access the organisation id from within the model.....

George

I have fixed the problem of getting the organisation_id into all the
records without hundreds of assignements in controllers...

I have an observer:

class BaseTableObserver < ActiveRecord::Observer
    cattr_accessor :current_organisation_id

    def before_validation(base_table)
        if base_table.organisation_id.blank? && !
@@current_organisation_id.blank? #only do it if its not already set
          base_table.organisation_id=@@current_organisation_id
       end
     end
end

And the class variable @@current_organisation_id is set in the
ApllicationController in a before filter.

This works..

I assume that since Ruby is single threaded that it is safe to use the
Class/Static variable?

Cheers
George

PS Using with_scope in around_filters appears to be a bit of a
controversial subject!
As does accessing session type variables from models. But in this case
I am happier with this solution than lots of separate assignments

In other words your problem was to set the organization in every
created model without pain ?

Ruby is not singlethreaded. You can even make your Rails app using
multiple Thread by calling setting threadsafe in Rails configuration.
I think Rails is threadsafe since 2.2 version. Instead of class
accessor you could use Thread.current[:organisation_id]

Robert Pankowecki