Update BookId to add the reference logic.

priv/repo/migrations/20250316152615_update_book_id_to_add_reference_logic.exs

@@ -0,0 +1,42 @@
+defmodule DecentralisedBookIndex.Repo.Migrations.UpdateBookIdToAddReferenceLogic do
+  @moduledoc """
+  Updates resources based on their most recent snapshots.
+
+  This file was autogenerated with `mix ash_postgres.generate_migrations`
+  """
+
+  use Ecto.Migration
+
+  def up do
+    drop constraint(:book_ids, "book_ids_book_id_fkey")
+
+    alter table(:book_ids) do
+      modify :book_id,
+             references(:books,
+               column: :id,
+               name: "book_ids_book_id_fkey",
+               type: :uuid,
+               prefix: "public",
+               on_delete: :delete_all
+             )
+    end
+
+    create index(:book_ids, [:book_id])
+  end
+
+  def down do
+    drop_if_exists index(:book_ids, [:book_id])
+
+    drop constraint(:book_ids, "book_ids_book_id_fkey")
+
+    alter table(:book_ids) do
+      modify :book_id,
+             references(:books,
+               column: :id,
+               name: "book_ids_book_id_fkey",
+               type: :uuid,
+               prefix: "public"
+             )
+    end
+  end
+end