ALTER TABLE `#__djc2_inv_counters`  ADD `doctype` ENUM('invoice','proforma') NOT NULL DEFAULT 'invoice'  AFTER `counter`;

ALTER TABLE `#__djc2_orders`  ADD `proforma_counter` INT NOT NULL DEFAULT '0'  AFTER `invoice_number`,  ADD `proforma_number` VARCHAR(64) NULL  AFTER `proforma_counter`;

