Basic Purchases Activity Model

The model begins when a need for items is identified, such as to fulfill a customer order or replenish inventory. The subsequent tasks, such as issuing a purchase order, receiving items, and making payments, are performed in sequence. When the items are received, the company records the purchase and updates its inventory. When payment is made, the system records the cash disbursement.

Context and Participants

The activity model identifies external participants, including suppliers, and the flow of activities between them. BPMN diagrams are used to map the interactions with suppliers, from placing the order to receiving and paying for goods.

Key BPMN Elements

• Tasks: Represent activities such as issuing a purchase order or paying the supplier.

• Gateways: Diamond symbols used to show decision points where the process can branch into different paths, such as accepting or rejecting goods.

• Intermediate Timer Events: Clock symbols represent delays, such as the time taken before making a payment.

• Message Flows: Show the exchange of documents or information between different parties in the process.

Collaboration Models

Collaboration diagrams in BPMN illustrate the interactions between different entities, like suppliers and the organization. Lanes can be used within the BPMN model to separate roles within the organization, such as purchasing, receiving, and accounts payable functions. This separation supports internal controls like segregation of duties, where different people handle ordering and payment.