Question

I am new to rails, and Im having hard time writing a query using rails’ methods.

What I am trying to accomplish is to have a Canteen model that has many Meals, however I want to only display meals that are being served that day.

So I created a Canteen model, that has_many Meals.
Then I created Served_date model, that belongs_to meal and Meal has_many Served_dates so we can specify multiple dates when the meal is being served.

How would I make query like this?

//P.S.: Served_date.where(served_at: Date.today) returns Served_dates that are being served today

Thanks !

Answer 1

Firstly, the model name should not be underscored by convention, hence you should use ServedDate instead of Served_date.

This query should give you what you need:

Meal.joins(:served_dates).where(served_dates: {served_at: Date.today})

Better yet, you can parameterize it and turn it into a scope to be more portable:

class Meal < ActiveRecord::Base
  scope :served_on, lambda{|date| joins(:served_dates).where(served_dates: {served_at: date}) }
end

And then call:

Meal.served_on(Date.today)