Why not to use has_many association extension over has_many with conditions

gistfile1.txt

Why not to use has_many association extension over has_many with conditions!

Has many is useful for adding in new functionality to the has_many association, however the problem with these entensions is 
that Rails doesn't cache them. So every time you call object.members.requested it makes a call to the database.

  has_many :organization_users
  has_many :members, through: :organization_users, source: :user 

  has_many :members, through: :organization_users, source: :user  do
      def requested
        where('organization_users.aasm_state = "requested"')
      end
      def active
        where('organization_users.aasm_state = "active"')
      end
      def disabled
        where('organization_users.aasm_state = "disabled"')
      end
  end


The same thing can be acheived by just making has_many with conditions like such:

  has_many :organization_users
  has_many :members, through: :organization_users, source: :user 
  has_many :active_members, through: :organization_users, source: :user,
    -> { where(organization_users: {aasm_state: "requested" })}