Question

Lets say I have a project model which has many members and many tasks.

class Project < ActiveRecord::Base
  has_many :memberships
  has_many :members, :through => :memberships, :class_name => 'User'
  has_many :tasks
end

When a task is created in the project, we keep a record of which user created it. Only users who are a member of the current project can

class Task < ActiveRecord::Base
  belongs_to :creator, :class_name => 'User'
  belongs_to :project
end

In my projects#show action, I want to find a project and display it along with it’s members, tasks and their creators. I try to eager load these things in order to speed up the query.

Since I am eager loading the searches members, and tasks can only have a creator who is a member, am I right in thinking that I don’t have to include the task’s creator specifically?

In other words, can I do this:

Search.includes(:members, :tasks)

or should I do this:

Search.includes(:members, :tasks => :creator)

Answer 1

I think you will need to explicitly include :creator otherwise it will query for it when you access the creator, because there is no way rails can know that creator is one of the already queried members