The Purchase Order System is fully integrated with the Inventory and Accounts Payable modules. This single entry approach reduces error throughout the purchasing, receiving, shipping, and sales process. When an item is purchased, cost is verified and/or updated. When this item is received, inventory is updated automatically. When the invoice is received, all corresponding costs can be verified and then released for payment in Accounts Payable. This process eliminates re-keying of data in accounting and provides complete audit trails and purchase history for all items. The system also has the ability to use Unvouchered Receipts which eliminates the need to hold Accounts Payable open until all invoices have been entered.