Sequel.migration do

  up do
    # create tests table
    create_table(:tests) do
      primary_key :id
      String :date_tag, null: false
      DateTime :created_at, default: Sequel::CURRENT_TIMESTAMP
      DateTime :updated_at, default: Sequel::CURRENT_TIMESTAMP
    end

    # add foreign keys to tests table
    alter_table(:tests) do
      add_foreign_key(:benchmark_id, :benchmarks, null: false)
      add_foreign_key(:hardware_id, :hardware, null: false)
    end

    # add the test ID link to results table; remove old links to hardware and benchmarks tables
    alter_table(:results) do
      add_foreign_key(:test_id, :tests, null: false)
      drop_column(:benchmark_id)
      drop_column(:hardware_id)
    end
  end

  down do
    drop_column(:results, :test_id)
    drop_table(:tests)
  end

end