Develop a data flow diagram from the following:

Myron was asked to investigate the current sales process in ABC Corp. During the investigation, Myron interviewed luck, the reception clerk in the sales department, and john, the clerk in the inventory department.
(a) According to Luck, once an order was received from a customer, he would first check the customer's credibility by accessing the Customer Master File. An order from a customer with bad credit would be rejected. He would then check the stock availability from inventory File. If the items were available, Luck would send the order to the inventory department for processing. If the items were out of stock he would call vendors to arrange immediate rush orders. When he got the confirmation from the inventory department that the filled order was sent to the customer, he would mark the order as a 'completed order 'in the daily sales file. At the end of the day, Luck would organize a Daily sales report from the Daily Sales file and submit the report to the sales Manager.
1. Prepare a data flow diagram about the process in (a).
(b)When John received orders from the sales department, he would pick the items from the warehouse to fill up the order. Then he would prepare and ship the package to the customer. After the package was shipped out to the customer, John would send the confirmation back to the sales department. John also would store the arriving shipments from vendors, and enter the records to update the inventory file.
2. Prepare a data flow diagram about the process in (b).
3. Consolidate two diagrams to create a combined data flow diagram.
4. Prepare a context diagram for this case.