gistfile1.php

<?php

function custom_delete_all_orders() {
  // Delete orders.
  $order_ids = db_query('SELECT order_id FROM {commerce_order}')->fetchCol();
  commerce_order_delete_multiple($order_ids);
  unset($order_ids);

  // Delete line items.
  $line_item_ids = db_query('SELECT line_item_id FROM {commerce_line_item}')->fetchCol();
  commerce_line_item_delete_multiple($line_item_ids);
  unset($line_item_ids);

  // Delete customer profiles.
  $profile_ids = db_query('SELECT profile_id FROM {commerce_customer_profile}')->fetchCol();
  commerce_customer_profile_delete_multiple($profile_ids);
  unset($profile_ids);

  // Delete payment transactions.
  $transaction_ids = db_query('SELECT transaction_id FROM {commerce_payment_transaction}')->fetchCol();
  commerce_payment_transaction_delete_multiple($transaction_ids);
  unset($transaction_ids);
}