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activerecordruby-on-rails-3arel

rails: how do I build an active-relation scope to traverse many tables?

I have these tables and relationships:

user has_many projects
project has_many tasks
task has_many actions

I would like to build a scope that allows me to select all of the current users actions, regardless of what project or task they belong to.

Thanks

Solution

  • I found something that works.

    In the Actions model: 

    def self.owned_by (user)
    joins("join tasks on actions.task_id = tasks.id").
    joins("join projects on tasks.list_id = projects.id").
    where("projects.user_id = ?" , user.id)
end

    From the console:

    u=User.find(1)
Action.owned_by(u).count

 => 521 # which is correct

    I'm mot sure if its the best way to do it as I'm a bit new to sql. I get the feeling it could be made more concise.

    EDIT Slightly better

     Action.joins(:task => [{:project => :user }]).where(:projects => {:user_id =>  user.id })