Ohm::Composite

Provides composite regular and unique indices for Ohm.

require "ohm/composite"

class Post
  include Ohm::Composite

  attribute :user_id
  attribute :date
  attribute :slug

  composite_index [:user_id, :date]
  composite_unique [:user_id, :slug]
end

Post.composite_find(user_id: 1, date: Date.today)
Post.composite_with(user_id: 1, slug: "lorem-ipsum")

Often times you need to find an instance by its uniqueness, or create it if it's not found.

For this purpose there's composite_with_or_create:

Post.composite_with_or_create(user_id: 1, slug: "lorem-ipsum")

This is guaranteed to be contention-safe: if two competing threads or processes end up in the create branch, only one will win and the other will receive the created instance. None of them will raise exceptions nor receive nils.

See UNLICENSE. With love, from Educabilia.