defmodule DaProductApp.Repo.Migrations.AddStanToQrValidations do
  @moduledoc """
  Add STAN field to qr_validations table for ReqPay verification.

  STAN (Systems Trace Audit Number) is used by NPCI for internal
  reconciliation and is passed from QR validation to payment request.
  """
  use Ecto.Migration

  def change do
    alter table(:qr_validations) do
      add :stan, :string, size: 6, comment: "Systems Trace Audit Number - 6 digit identifier for NPCI reconciliation"
    end

    create index(:qr_validations, [:stan])
  end
end