defmodule Mobilizon.Repo.Migrations.TagsRelations do
  use Ecto.Migration

  def up do
    create table(:tag_relations, primary_key: false) do
      add :tag_id, references(:tags, on_delete: :delete_all), null: false, primary_key: true
      add :link_id, references(:tags, on_delete: :delete_all), null: false, primary_key: true
      add :weight, :integer, null: false, default: 1
    end
    create constraint(:tag_relations, :no_self_loops_check, check: "tag_id <> link_id")
    create index(:tag_relations, [:tag_id], name: :index_tag_relations_tag_id)
    create index(:tag_relations, [:link_id], name: :index_tag_relations_link_id)
  end

  def down do
    drop constraint(:tag_relations, :no_self_loops_check)

    drop index(:tag_relations, [:tags_id])
    drop index(:tag_relations, [:link_id])
    drop table(:tag_relations)
  end
end