The Purchase Request module introduces the concept of Purchase Requests which are central points to collect purchase requests generated by other process from Tryton.
A purchase request defines the need to purchase a product. It is linked to a warehouse and possibly a supplier, it contains a ideal purchase date and an expected supply date. A purchase request can be in one of these states:
A draft purchase request is a request that is not linked to a purchase.
A Purchased request is a request that is linked to a purchase which is not in state Done or Cancel.
A purchase request is in state Done if it is linked to a Purchase which is in state Done.
A purchase request is in state Cancel if it is linked to a Purchase which is cancelled.
A wizard allows to create purchases based on a selection of draft purchase requests. The new purchases contains one purchase line by product and unit and group them by warehouses and by suppliers. Once the purchases are created, the corresponding purchase requests are set to the state Purchased.