How can I update and save one model from another in Rails?

Question

In my program, I have a model, Calorie, that takes what a person ate and gives them a point total. After that point value is calculated for each day\'s nutritional information,

Answer 1

I'm assuming your Calorie model has a has_one relationship with the User, and User has_many Calories.

In Calorie model:

after_save :update_user_points

def update_user_points
    self.user.update_calorie_points!
end

In User model:

def update_calorie_points!
    self.update_column(:points, self.calories.sum(:points))
end