A very important aspect of the entrée system is its ability to track purchase orders. Not only do purchase orders provide you with a means to keep on top of incoming product that your buyers have ordered, but also to maintain inventory levels and update cost and pricing. In order to take advantage of these features, the vendor file must be defined. It is really the core of the purchasing and accounts payable system. This section will give you an in-depth tour of the vendor file and all of the fields of information stored within.