Preferred find method: :has_many, :belongs_to relationship

rubyonrails-talk
1

I'm looking for some clarification regarding finds in a :has_many, :belongs_to relationship. Consider:

class User < ARB   has_many :tasks end

class Task < ARB   belongs_to :user end

Both of these methods in a controller yield the same result:

def find_tasks_for_user   @user = User.find(params[:id])   @tasks = Task.find_all_by_user_id(params[:id]) end

def find_tasks_for_user   @user = User.find(params[:id])   @tasks = @user.tasks end

I'm assuming that the latter is the more idiomatic of the two. But is there anything "wrong" with the first approach?

2

No, but the second approach lends itself to being optimized using :include - thusly:

def find_tasks_for_user   @user = User.find(params[:id], :include => :task)   @tasks = @user.tasks end

Or the :include can be added to the model definition.

There may also be some advantages in that @user.tasks will cache the value, so that if code in the view asks for it again, it will avoid another trip to the DB.