# frozen_string_literal: true
# This migration creates the `versions` table, the only schema PT requires.
# All other migrations PT provides are optional.
class CreateVersions < ActiveRecord::Migration[6.1]
  # The largest text column available in all supported RDBMS is
  # 1024^3 - 1 bytes, roughly one gibibyte.  We specify a size
  # so that MySQL will use `longtext` instead of `text`.  Otherwise,
  # when serializing very large objects, `text` might not be big enough.
  TEXT_BYTES = 1_073_741_823

  def change
    create_table(:versions) do |t|
      t.string(:item_type, { null: false })
      t.bigint(:item_id,   null: false)
      t.string(:event,     null: false)
      t.string(:whodunnit)
      t.text(:object, limit: TEXT_BYTES)

      t.datetime(:created_at)
    end
    add_index(:versions, [:item_type, :item_id])
  end
end