PARTICIPANTS_SQL = <<~EOS
  CREATE VIEW "participants" AS
  SELECT "users"."id" AS "participant_id",
         "users"."email" AS personal_email,
         "users"."language" AS language,
         "participations"."id" AS "participation_id",
         "personal_profiles"."id" AS "personal_profile_id",
         "personal_profiles".* FROM "users"
  INNER JOIN "participations"    ON "users"."id" = "participations"."participant_id"
  INNER JOIN "events"            ON "events"."id" = "participations"."event_id"
  INNER JOIN "conferences"       ON "events"."conference_id" = "conferences"."id"
  LEFT JOIN "personal_profiles"  ON "personal_profiles"."conference_id" = "events"."conference_id"
                                AND "personal_profiles"."user_id" = "users"."id";
EOS

class AddParticipantsView < ActiveRecord::Migration[4.2]
  def up
    execute PARTICIPANTS_SQL
  end

  def down
    execute 'DROP VIEW "participants"'
  end
end