Indexing Enum Columns in Rails 8 #

In Rails 8, enum definitions are stricter, and new best practices for indexing have emerged.

Key Changes in Rails 8 Enum Handling #

• enum now requires explicit mapping. For integer enums: (:status, { active: 0, inactive: 1 }). For String enums: (:status, { active: active, inactive: inactive }).
• _prefix and _suffix methods are changed, there is no need of the underscore. prefix: true is used than _prefix: true.

With these changes, you must ensure indexing is correctly applied to enum columns using the new syntax:

class User < ApplicationRecord
  enum :status, { active: 0, inactive: 1, banned: 2 }, validate: true

  # New Rails 8 syntax requires explicit naming for methods
  enum :role, { admin: 3, editor: 4, viewer: 5 }, prefix: true
end

Querying with indexes remains unchanged:

User.where(status: :active)
User.where(user_role: :admin)

However, defining indexes in migrations now aligns with the stricter syntax:

class AddIndexToUsersRails8 < ActiveRecord::Migration[8.0]
  def change
    add_index :users, :status, name: "index_users_on_status"
  end
end