Video Rental System $($VRS$)$

Video$-$Rental System is a small Program for video rental store. The store lends videos to customers for a fee, and purchases its videos from a local supplier. A customer wishing to borrow a video provides the empty box of the video they desire, their membership card, and payment $$ payment is always with the credit card used to open the customer account. The customer then returns the video to the store after watching it$.$ If a loaned video is overdue by a day the customer's credit card is charged, and a reminder letter is sent to them. Each day after that a further card is made, and each week a reminder letter is sent. This continues until either the customer returns the video, or the charges are equal to the cost of replacing the video. New customers fill out a form with their personal details and credit card details, and the counter staff give the new customer a membership card. Each new customer's form is added to the customer file. The local video supplier sends a list of available titles to Video$-$Rental System, who decide whether to send them an order and payment. If an order is sent, then the supplier sends the requested videos to the store. For each new video a new stock form is completed and placed in the stock file. Using DFD components $($External Entity, Process,Output,Data Flow and Data Store$)$

Draw a Context Diagram $($Level $0),$ a Level $1$ and Level $2$ diagram for VRS$?$

$$ Context diagrams $$ context diagram DFDs are diagrams that present an overview of the system

and its interaction with the rest of the $$world$.$

$$ Level $1$ data$-$flow diagrams $$ Level $1$ DFDs present a more detailed view of the system than context diagrams, by showing the main sub$-$processes and stores of data that make up the system as a whole.

$$ Level $2($and lower$)$ data$-$flow diagrams $$ a major advantage of the data$-$flow modelling

technique is that, through a technique called $$levelling$,$ the detailed complexity of real world systems can be managed and modelled in a hierarchy of abstractions$.$ Certain elements of any dataflow diagram can be decomposed $($exploded$)$ into a more detailed model a level lower in the hierarchy.