Converting an Array of Objects to Activerecord::Relation

Converting an array of objects to ActiveRecord::Relation

How can I convert an Array of objects to an ActiveRecord::Relation? Preferably without doing a where each time.

You cannot convert an Array to an ActiveRecord::Relation since a Relation is just a builder for a SQL query and its methods do not operate on actual data.

However, if what you want is a relation then:

• for ActiveRecord 3.x, don’t call all and instead call scoped, which will give back a Relation which represents the same records that all would give you in an Array.

• for ActiveRecord 4.x, simply call all, which returns a Relation.

When running a def self.subjects type method on an ActiveRecord::Relation, how do I access that ActiveRecord::Relation object itself?

When the method is called on a Relation object, self is the relation (as opposed to the model class it’s defined in).

How can i convert an array to an rails ActiveRecord::Relation without changing array order?

This seems to do what you want (res1 ... res5 should be Restaurant objects)

ids = [res1,res5,res2,res4,res3].map(&:id)
@places = Restaurant.where(id: ids).order("FIELD(id, #{ids.join(',')})").all

More info, Maintaining order in MySQL "IN" query

Rails 5 - How to convert from array to activerecord relation?

If you just want the associations for the current user and you've set up the 'has_many' correctly you can do...

current_user.associations.order(created_at: :desc)

This will give you all the association records, and (of course) the current_user information like id and name are available directly from the current user.

This will be an ActiveRecord::Relation and you can iterate over it so, yes, it'll behave like an array. If you want all the list, you want an array or array-like structure.

Rails 5 rspec - convert object to ActiveRecord Relation

The simple way to do it is to use create_list and return an ActiveRecord relation, but if I were you I'd rethink it to use stubs.

let(:array) do
  list = create_list(:class_example, 4)
  ClassExample.where(id: list.map(&:id))
end

Ruby: Convert an array or hash to an activerecord relation

What you want to do start from the inverse end (Category) and use an aggregate in the ORDER clause.

Category.joins(:articles)
        .order('SUM(articles.impressions_count) DESC')
        .group(:id)
        .limit(5)

---

irb(main):005:0> Category.joins(:articles).order("SUM(articles.impressions_count) DESC").group('categories.id').limit(5)
  Category Load (1.5ms)  SELECT  "categories".* FROM "categories" INNER JOIN "articles" ON "articles"."category_id" = "categories"."id" GROUP BY categories.id ORDER BY SUM(articles.impressions_count) DESC LIMIT $1  [["LIMIT", 5]]
=> #<ActiveRecord::Relation [#<Category id: 4, name: "C#", created_at: "2017-11-15 15:06:32", updated_at: "2017-11-15 15:06:32">, #<Category id: 3, name: "JavaScript", created_at: "2017-11-15 15:06:32", updated_at: "2017-11-15 15:06:32">, #<Category id: 1, name: "Simula", created_at: "2017-11-15 15:03:37", updated_at: "2017-11-15 15:03:37">, #<Category id: 2, name: "Haskell", created_at: "2017-11-15 15:06:32", updated_at: "2017-11-15 15:06:32">]>

And you should create a class method - not an instance method as this is basically just a scope and does not make sense to call on an instance.

class Category < ApplicationRecord
  has_many :articles

  def self.order_by_article_impressions
    self.joins(:articles)
        .order('SUM(articles.impressions_count)')
        .group(:id)
  end

  def self.top_5_visited
    order_by_article_impressions.limit(5)
  end

  # Or use `scope` which is just syntactic sugar
  scope(:top_5_visited) -> { order_by_article_impressions.limit(5) }
end

How to Convert ActiveRecord_Relation to an normal array in rails

Relation has to_a method, which does exactly that. It is used internally for methods like any?

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