Please help me with an analysis Data Flow Diagram for the following our team has been hired to analyze the requirements of a small book store. The owner of the store buys and sells only premium used paperbacks. She would like to expand her business by offering to sell and buy books over the Internet. She realizes that she will have to automate her manual processes. Currently, she keeps track of the books in the store by making an entry in an alphabetized file. She keeps track of customers by noting in a file their names, addresses, phone numbers, email addresses and credit worthiness. She allows credit worthy customers to charge their purchases and bills them once a month. All others pay cash.

Analyze the bookstore's current system by drawing a context level DFD. Show the external entities and the data flows into and out of the system.

Explode your context diagram to show processes internal to the system. At this level also show the data stores. Make sure you have no black holes or miracles.

To fully describe the system, you should explode one or more internal processes to show sub-processes. The set of diagrams you have just created is called the analysis data flow diagram. The analysis DFD helps you document the existing system and begin thinking about improvements.