Video-Rental LTD case study Video-Rental LTD is a small 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 bo of the video they desire, their membership card, 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. "f a loaned video is overdue by a day the customer#s credit card is charged, and a reminder letter is sent to them. $ach day after that a further card is made, and each wee% a reminder letter is sent. This continues until either the customer returns the video, or the charges are e&ual to the cost of replacing the video. 'ew customers (ll out a form with their personal details and credit card details, and the counter sta) give the new customer a membership card. $ach new customer#s form is added to the customer (le. The local video supplier sends a list of available titles to Video-Rental LTD, who decide whether to send them an order and payment. "f an order is sent then the supplier sends the re&uested videos to the store.
Example Case Study – Pizza Supreme A large pizza pizza business makes pizzas and sells them. them. The pizzas are are manufactured manufactured and kept in cold storage for not more than two weeks. The business is split into a number of functional units. There is Production Control, Manufacturing, Manufacturing, Stores, Accounts, Sales, Shipping and Purchasing. Production Control are responsible for organising which pizzas to produce in what order and in what quantit. The need to schedule the production of the pizzas according to the current and e!pected sales orders together with the number of pizzas alread alread in Stores. Manufacturing Manufacturing take the raw materials from the Stores and manufacture pizzas returning the completed goods to the Stores. Accounts deal with the paments for the pizzas when deli"ered to the customer and the pament to the suppliers of the raw materials. Sales deal with customer orders whilst Purchasing organise the buing of raw material from suppliers. Shipping manage the packing and deli"er of the goods to the customer with a deli"er note.
#hen a sales order is recei"ed b sales the record what is being ordered and b whom. The also record the details of the e!pected date of deli"er. Production Control access this information and make sure that, if required, pizzas are produced b Manufacturing and are read in Stores for when the deli"er needs to be made.
After the deli"er deli"er is made Accounts Accounts make sure sure that the customer customer recei"es an an in"oice and that that pament for the the in"oice is recei"ed recei"ed at which which time a receipt is issued. Purchasing Purchasing look at the current stock of raw materials and b using current stock le"els, supplier turn around times and
quantit to be ordered decide what needs to be ordered on a dail basis. Their aim is ne"er to run out of an ingredient but to minimise the amount of raw material kept in stock.
Case–study Correspondence courses
A college o)ers correspondence courses to students. $ach course lasts *+ wee%s and is based on a wee%ly study module and progress test. At the end of the course students sit an invigilated eamination.
The college Registrar deals with en&uiries and applications, and students applying who have sucient &uali(cations are as%ed to register by completing and submitting an application form.
After approval by the Academic Director, the application form is returned to the Registrar who creates a student (le. The Accounts department receive the application form and using information from the student (le creates an invoice that is sent to the student. ayments made are registered on the invoice (le. The (rst batch of student material and tests is issued from the library only to students who have paid fees this information is ta%en from the invoice (le/.
rogress tests are mar%ed by academic sta) and the results, together with comments, are sent out with net wee%0s study bloc%. The library will only issue study material1progress tests when a student has returned test answers from the previous wee%.
Case–study
Animal Park
The %eepers in an animal par% loo% after the feeding of the animals. $ach animal is located in a di)erent area of the par%. $ach area has its own %eeper who reports to the head %eeper.
The head-%eeper maintains a record of the sorts of food that each animal species or type in the par% should be fed, and in what &uantities. There is no distinction made between di)erent animals of the same species. The %eepers access the information so they %now what to feed each animal type. $ach animal type may be given more than one type of food, and each type of food may be fed to a number of animal types. $ach day the %eepers will ta%e out the food needed for the animals in their care and record this on the information system. These food types can be perishable or non-perishable according to their shelf life. 2or eample, fresh fruit and vegetables would be perishable where tinned produce or cereals would be considered to be non-perishable. The oce sta) %eep a trac% of the food supplies. They monitor which foods are running low every two or three days and draw up a list of that which needs to be ordered. "n order to help them, the information system contains details about re-order &uantities and re-order levels. 3ometimes they may need to read4ust their re-order levels. A number of suppliers are used, and their names, addresses and telephone numbers are %ept in the system. 5ecause of the large &uantities re&uired and the diculty of obtaining some foods at certain times of the year, there is more than one possible supplier for each type of food. 6ost of the ordering is done via the telephone. A standard order form is then created. The order form usually contains details of more than one food type to be ordered from a particular supplier. The order also contains details of the date of the order and what &uantities are re&uired for each food type. 7hen deliveries are received, the %eepers chec% the delivery note against the goods received, amend it if necessary and pass it on to the oce. 8ere it is chec%ed against the orders placed. "t they agree, this is recorded in the system. The oce sta) chec% the received orders against an invoice sent by the supplier. "f they agree, payment is be made. Any discrepancies are ta%en up with the supplier, and the supplier#s response is noted in the system. 6ost suppliers send an invoice each month.
Case–study Doctors Sur!ery
A doctors0 surgery consists of (ve doctors a receptionist and a manager. They need an information system to help them to run the facility. A patient may ring the surgery to ma%e an appointment with a doctor. $ach patient nominally has a doctor associated with him or her but they may often opt to see any doctor in the surgery that is available. The receptionist sees which doctors are on duty on which days and o)ers appointment alternatives from which the patient may choose. "f an appointment is not available within a short time and the patient must be seen &uic%ly they are as%ed to attend an emergency surgery that ta%es place every evening between 9 and : p.m. The appointment can be 9, ;+ or *+ minutes long, dependent on the reported reason for seeing the doctor. This reason is recorded on the system. 3ometimes patients ring to cancel appointments. Appointments may be made for up to si wee%s in advance. Appointments that are more than < wee%s old are automatically deleted from the system. 3ome appointments are for a doctor to go and visit a patient at home when the patient cannot come to the surgery. $very day one of the doctors is available for home visits in the afternoon. A record is %ept of each patient and the treatments they have received for any ailments they may have had. 8ere are recorded many details such as allergies, details of which drugs patients have been administered in which &uantities and when. Also relevant personal details of each patient are recorded. Typically the doctor who sees a patient will want access to this information before deciding on the relevant treatment to give. 7hen the doctor prescribes treatment, details will be recorded in the patient0s record. Repeat prescriptions are automatically produced by the system and are available for collection at the surgery by the patient. At any time a doctor may suspend or cancel the prescriptions. atients may register with the surgery providing the number registered to each doctor is not above a certain maimum. 3ometimes patients die or leave the area. "n this case the patient is
removed from the system and their details are archived. The manager is responsible for dealing with this aspect. 3uppose you are given the details of a small mail order catalogue system that allows people to shop from home. 7hen a customer receives the catalogue and wants to buy something, they can telephone, fa or email their order to the company. The company gets the order and sends the goods and an invoice. 7hen the customer receives the goods with a delivery note, they send payment and receive a receipt for their payment. The (rst thing we must do is model the main outputs and sources of data in the scenario above. Then we draw the system bo and name the system. 'et we identify the information that is =owing to the system and "rom the system. 8ere is the Level + also %nown as the contet diagram/ D2D for the 6ail >rder system?
7hen a patient arrives at 6osspar% 3urgery with a repeat prescription re&uest, the receptionist chec%s the prescription (le and writes out a prescription. This has to be authorised by the doctor before being passed to the resident chemist for dispensing. The chemist then gives the prescription to the patient. "f the patient is entitled to free prescriptions, the chemist veri(es this and (lls in the appropriate details on a form, which is (led in the free prescriptions (le. >therwise the chemist ta%es the appropriate amount of money from the patient and gives them a receipt.
Level ; D2D The net stage is to create the Level ; Data 2low Diagram. This highlights the main functions carried out by the system. As a rule, we try to describe the system using between two and seven functions - two being a simple system and seven being a complicated system. This enables us to %eep the model manageable on screen or paper.
7hen 2lash"T are interviewing and selecting new employees for their company, they as% applicants to send their application forms and their @Vs to personnel. The personnel department then chec%s these forms for completeness and, if found to be complete, they are stored in the applications (le. >therwise these forms are returned to applicants for resubmission. The applications are then scrutinised for possible interviewees. Any candidates not considered suitable for the post are sent a refusal letter. 3uitable candidates are re&uested to come in for
interview. After interviews have ta%en place, a decision on the most suitable candidate is ta%en and they are o)ered the post. The interviewees who have been unsuccessful are sent a refusal letter.
The (nal stage in data =ow modelling is to ta%e each Level ; 2unction and brea% it down into its constituent parts. These parts are the fundamental rocesses which ma%e up the function.
6avisban% 8igh 3chool has a library that lends boo%s to sta) and students. upils are allowed to borrow si boo%s and teachers are allowed to borrow ten. 7hen someone borrows a boo% the library boo% (le is updated, as is the borrower (le. $veryone issued with a boo% has it for a period of one month, after which time they are sent a reminder. "f, after si months, they haven#t returned the boo%, they are sent a bill for the cost of recovery of the boo%.
A #ank $ana!er actor provides %e& account details to the 'pen Account process which results in Customer details being persisted in the Customer Data(ase data store and Account details being persisted in the Account Data(ase data store. Although we have used the phrase results in0 as part of this eplanation, the D2D implies no such cause and e)ectB all it shows is that the 'pen Account process can read in data from the #ank $ana!er interface and write out data to the Customer Data(ase and Account Data(ase data stores in no particular order. A Customer actor using the 'nline #ankin! Login process must provide some data in the form of a set of Lo!in credentials such as a user name and password. A Customer actor can receive a $oney amount from the )it*dra& process and can supply a $oney amount to the Deposit processB in either case causing although this causation cannot be eplicitly modeled/ an Account (alance update to the Account Data(ase data store. A Customer actor can initiate the Trans"er +unds process, to which he or she must provide an Account destination and money amount. The Trans"er +unds process can send a $oney amount to another ban% via the 't*er #ank interface. Cust li%e the Customer actor, a T*ird Party actor can ma%e use of the Deposit process but obviously not the )it*dra& process/ by supplying a $oney amount.
Estate a!ency case study @lients wishing to put their property on the mar%et visit the estate agent, who will ta%e details of their house, =at or bungalow and enter them on a card which is (led according to the area, price range and type of property . otential buyers complete a similar type of card which is (led by buyer name in an A binder. 7ee%ly, the estate agent matches the potential buyer0 re&uirements with the available properties and sends them the details of selected properties. 7hen a sale is completed, the buyer con(rms that the contracts have been echanged, client details are removed from the property (le, and an invoice is sent to the client. The client receives the top copy of a three part set, with the other two copies being (led. >n receipt of the payment the invoice copies are stamped and archived. "nvoices are chec%ed on a monthly basis and for those accounts not settled within two months a reminder the third copy of the invoice/ is sent to the client. @reate a contet diagram for this $state Agency case study. A discussion on this review &uestion can be found at the end of this chapter. •
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5uses come to a garage for repairs. A mechanic and helper perform the repair, record the reason for the repair and record the total cost of all parts used on a 3hop Repair >rder. "nformation on labor, parts and repair outcome is used for billing by the Accounting Department, parts monitoring by the inventory management computer system and a performance review by the supervisor. roblems and $ercises 3olutions
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;. Esing the eample of a retail clothing store in a mall, list relevant data =ows, data stores, processes, and sources1sin%s. >bserve several sales transactions. Draw a contet diagram and a level-+ diagram that represent the selling system at the store. $plain why you chose certain elements as processes versus sources1sin%s. A suggested contet diagram and level-+ diagram are provided below.
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*. @hoose a transaction that you are li%ely to encounter, perhaps ordering a cap and gown for graduation, and develop a high-level D2D, or contet diagram. Decompose this to a level-+ diagram. A suggested contet diagram and a level-+ diagram are provided below.
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Context Dia!ram
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<. $valuate your level-+ D2D from roblem and $ercise * using the rules for drawing D2Ds in this chapter. $dit your D2D so that it does not brea% any of these rules. 3tudents should go through the rules discussed in this chapter and presented in Table 9!* and 2igure 9!:/ one at a time and chec% each of their data-=ow diagrams. Alternatively, if the students are using a @A3$ tool to create their data-=ow diagrams, the @A3$ tool may be used to automatically chec% for errors in the diagrams. There are no rule violations in the eample D2Ds, but we cannot verify that there are no logical problems until we decompose the diagrams to a primitive level. >ne obvious missing system capability is how to handle invalid ordersB typically, processes to handle abnormal conditions, li%e invalid orders, are shown on primitive or at least low-level diagrams.
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. @hoose an eample li%e that in roblem and $ercise *, and draw a contet diagram. Decompose this diagram until it doesn0t ma%e sense to continue. 5e sure that your diagrams are balanced, as discussed in this chapter.
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3tudents may choose a variety of situations to use for the nth level data-=ow diagrams for this answer. 5asically, students should continue the process of decomposition until they have reached the point where no subprocess can logically be bro%en down further i.e., each process meets the de(nition of a primitive process/. 3ee the level-; data-=ow diagram for this eercise, which shows a sample decomposition of the process titled 2inaliFe >rder from the level-+ data-=ow diagram provided for roblem and $ercise <. The italiciFed/ labels for processes and sources1sin%s without borders represent the origin or destination of =ows that pass between this subsystem and other system components. 'ote that the Goods 3old 2ile is a potential blac% hole or should possibly be treated as a sin%.
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9. Refer to 2igure 9-** A and 5, which
contains drafts of a contet and a level-+ D2D for a university class registration system. "dentify and eplain potential violations of rules and guidelines on these diagrams. 3ome errors and peculiarities in these diagrams include?
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H "n the level!+ diagram, the data store, @lass Roster, does not have the data =ow, 3cheduled @lasses, =owing into it, rather this data =ow connects processes * and
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:. 7hy should you develop both logical and physical D2Ds for systemsI 7hat advantage is there for drawing a logical D2D before a physical D2D for a new information systemI hysical data-=ow diagrams help you better understand the people and1or computer systems that are used in the overall system0s processing. Logical data-=ow diagrams help you better understand the essence of the system, the data and the processes that transform them, regardless of actual physical form. 2urther, the new logical data-=ow diagrams can then show any additional functionality necessary in the new system, to indicate which, if any, obsolete components have been eliminated, and any changes in the logical =ow of data between system components, including di)erent data stores. The data-=ow diagrams for the new physical system can then be constructed with the data=ow diagrams for the new logical system as a guide.
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J. This chapter has shown you how to model, or structure, 4ust one aspect, or view, of an information system, namely the process view. 7hy do you thin% analysts have di)erent types of diagrams and other documentation to depict di)erent views e.g. process, logic, and data/ of an information systemI The various views e.g., process, logic, data/ of an information system each have their own uni&ue characteristics and provide the most relevant information to di)erent information system specialists. This variety is best understood, epressed, and managed by using diagrams and documentation that are speci(cally tailored for each view of the system. 2or eample, data-=ow diagrams are useful for capturing the =ow of data through business processes, but they are not useful for describing the forms and relationships among data. As information systems become larger and more comple, it becomes even more important to use the right tool and techni&ue to develop each component of an information system. >ne techni&ue that captured all aspects of an information system model on one diagram or in one notation would li%ely be too comple for systems professionals to handle.
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@onsider the D2D in 2igure 9!*<. List three errors rule violations/ on this
D2D. Three ma4or errors in 2igure 9!*< are?
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H rocess ;.+ */ has only inputs, ma%ing it a blac% hole.M H Data =ow D29 should not move directly from source $; to data store D3; without (rst going through a process. H Data =ow D2; should not move directly from source $; to sin% $* without (rst going through a process. H >ther peculiarities such as rocess ;.+ has label * and the data store has only a label, not a number/ are only that, not errors.
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N. @onsider the three D2Ds in 2igure 9!*. List three errors rule violations/ on these D2Ds. These diagrams show the decomposition of process ; on the level-+ diagram. Three particular logical errors in 2igure 9!* are?
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H The data store D3;, not D3*, should be represented on the level-; diagram. H Data =ow D2< should be an out=ow on the level-; diagram, and data =ow D2: should not be on the level-; diagram. H rocess ;..* has no inputs and is thus a miracle.M
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;+. 3tarting with a contet diagram, draw as many nested D2Ds as you consider necessary to represent all the details of the employee hiring system described in the following narrative. Oou must draw at least a contet diagram and a level-+ diagram. "n drawing these diagrams, if you discover that the narrative is incomplete, ma%e up reasonable eplanations to complete the story. 3upply these etra eplanations along with the diagrams. The ro4ects, "nc. narrative is provided in the tetboo%./ A suggested contet diagram and level-+ diagram are provided below. •
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;;. a. 3tarting with a contet diagram, draw as many nested D2Ds as you consider necessary to represent all the details of the system described in the following narrative. "n drawing these diagrams, if you discover that the narrative is incomplete, ma%e up reasonable eplanations to complete the story. 3upply these etra eplanations along with the diagrams. The 6aimum 3oftware narrative is provided in the tetboo%./ b. AnalyFe the D2Ds you created in art a. 7hat recommendations for improvements in the help des% system at 6aimum can you ma%e based upon this analysisI Draw new logical D2Ds that represent the re&uirements you would suggest for an improved help des% system. Remember, these are to be logical D2Ds, so consider improvements independent of technology that can be used to support the help des%. The sample contet and level-+ data-=ow diagrams represent one possible way to model the help des% process described in this &uestion. "n our solution, we have chosen to include the processes performed by the consultants and operators as subsystems within the system rather than as sources1sin%sB this adds detail, but allows bottlenec%s in these processes to be corrected. 'ote that the data stores are repeated in the level-+ diagram, to avoid ecessive crossing of data =ow lines. 3everal processes could be eploded further, but the student would probably have to ma%e many assumptions to do so.
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There are a number of ways that the students could choose to improve this system. 2or eample, with the current system a customer may have to eplain his problem and1or &uestion over and over to multiple people? an operator and possibly several consultants. The customer may begin to believe that he is getting the run-aroundM characteristic of a large bureaucracy. >ne way to avoid this potential problem is to let the initial operator have access to the customer problem database so that when the caller is handed o) to a consultant the customer0s already opened problem (le will go along with him. "n addition, the operator could have sucient information and the option to direct the call to the proper consultant. Alternatively, clients could call the assigned consultant directly on follow-up calls to an initial call for help.
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As% your students for characteristics of a D2D that imply areas for improvement. ossible answers are? processes that simply collect and pass on information rather than transforming data, collecting the same information into several processes, placing untransformed data into data stores thus causing un%nown delays in processing this data, or cycles or loops that have no apparent termination.
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A suggested contet diagram and level-+ diagram are provided below. • •
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b. 6odify 8oosier 5urger0s level-+ diagram 2igure 9!9/ to re=ect the changes mentioned in the case. Although student answers will vary, a suggested answer is provided below.
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c. repare level-; diagrams to re=ect the changes mentioned in the case. 3tudent answers will varyB to facilitate discussion, a level-; diagram is provided below. • •
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d. $change your diagrams with those of another class member. As% your classmate to review your diagrams for completeness and consistency. 7hat errors did he or she (ndI @orrect these errors. $ncourage students to review the data-=ow diagramming rules presented in Table 9!*. Esing these rules as a guide, students should then evaluate their classmate0s diagrams.
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<. $vergreen 'urseries @ase $ercises 3olutions
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a. @onstruct a contet data-=ow diagram, illustrating $vergreen 'urseries0 wholesale system.
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3tudent interpretations will vary. A suggested answer follows. Context-Le,elDia!ram
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@onstruct a level-+ diagram for $vergreen 'urseries0 wholesale system.
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3tudent interpretations will varyB a suggested answer follows.
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c. Esing the level-+ diagram that you constructed in part b, select one of the level-+ processes, and prepare a level-; diagram.
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A suggested answer is provided below. Le,el-.Dia!ram
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d. $change your diagrams with those of another class member. As% your classmate to review your diagrams for
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completeness and consistency. 7hat errors did he or she (ndI @orrect these errors. $ncourage your students to review the data-=ow diagramming rules presented in Table 9! *. Esing these rules as a guide, your students should then evaluate their classmates0 diagrams.
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#road&ay Entertainment Co/0 1nc/ Case 2uestions Solutions
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;. Does the contet diagram in 5$@ 2igure 9!; represent an accurate and complete overview of the system as described in this case for re&uirements collected during the analysis phaseI "f not, what is wrong or missingI "f necessary, draw a new contet diagram in light of what is eplained in this case. 7hy might a contet diagram initially drawn at the end of pro4ect initiation and planning need to be redrawn during the analysis phaseI lease refer to the updated contet diagram in 2igure 5$@ Answer 9!; at the end of this section. There should be a data =ow from the system to the $ntertainment Trac%er that represents the re&uest for a rental etension. There also needs to be a data =ow from the $ntertainment Trac%er to the system and one from the system to the customer to represent the acceptance or denial of a rental etension re&uest. There should also be a data =ow from the employee to the system representing the re&uest for the list of new products re&uested by customers. A data =ow from the system to the employee should be shown to represent the list of new products re&uested by the customers. There should be a data =ow from the $ntertainment Trac%er to the system representing the customer0s sales and rental history. There should also be a data =ow from the system to the customer that represents the employees0 favorite pic%s. The contet diagram might change during the analysis phase, because new data =ows and sources1sin%s could be discovered after more analysis of the re&uirements of the system is done.
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*. "n the contet diagram of 5$@ 2igure 9-;, why is the Rental $tension Re&uest data =ow shown as an in=ow to the systemI 7hy is the Rental 3tatus data =ow shown as an out=ow from the systemI Do you agree with these designations of the two data =owsI 7hy or why notI The Rental $tension Re&uest data =ow is an in=ow into the system because the data are originating from an eternal source, the customer, and are input into the system. The Rental 3tatus data =ow is an out=ow from the system because the destination of that data is the @ustomer sin%. The student should agree with the designations of these data =ows because they logically represent the data moving between the customer and the system. The Rental $tension Re&uest will cause the system to generate the Rental $tension Accept1Denial data =ow. Rental 3tatus is generated by a customer re&uest, which is assumed on this diagram, and would appear on some eplosion diagram. 3tudents may recommend that a Rental 3tatus Re&uest data =ow be added to the contet diagram shown in 5$@ 2igure 9!;.
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<. The store manager is not shown in the contet diagram in 5$@ 2igure 9!;, ecept implicitly as an $mployee who enters 2avorite ic%s. 5ased on the descriptions in this case, does it ma%e sense that store managerM does not appear on the contet diagramI "f not on the contet diagram, where might store manager appearI As an eternal entity on a lower-level diagramI As a process or data store on a lower-level diagramI 5ased on the description in this case, are there any eternal entities missing on the contet diagram of 5$@ 2igure 9!;I The distinction between the store manager and the other employees is not important in describing this system and its interaction with eternal entities, so the store manager does not need to eist as a separate source1sin% from the employee source1sin%. The store manager cannot be added as a source1sin% in a lower-level diagram because that would unbalance the diagrams. The store manager should not be represented as a data store or a process on a lower level diagram, because he1she does not store data or process data with the system. There are no missing eternal entities on the contet diagram that directly interact with the system.
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. 5ased on the descriptions in this case of each data =ow from the contet diagram, draw a level-+ data-=ow diagram for 6y5roadway using 6icrosoft Visio begin by drawing the contet diagram, then eplode to level-+/. 5e sure it is balanced with the contet diagram you might have drawn in answer to Puestion ;. 3uggested answers are provided below. 5$@ Level!+ •
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9. 7rite pro4ect dictionary entries using standards given to you by your instructor/ for all the data stores shown in the level+ diagram in your answer for Puestion . Are there other data stores hidden inside processes for your level-+ diagramI "f so, what %inds of data do you anticipate are retained in these hidden data storesI 7hy are these data stores hidden inside processes rather than appearing on the level-+ diagramI 7e do not provide an entry for every data store since each instructor may have di)erent epectations. 8ere is an eample of a pro4ect dictionary entry for data store D;? @omment 2ile, typical of dictionary contents? •
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De(nition "denti(er? @omment 'ame? @omment 2ile Remar%? 3tores the comments that customers ma%e about products. @omments are &ualitative statements that eplain a customer#s reactions to a product. @omments can be positive or negative, or may simply describe, in the customer#s own words, what he or she considers to be the characteristics of the product, appropriateness for di)erent audiences, or &uality. @ontents $ntity? @omment Attributes? @omment "D, @omment, Date, "denti(er of who made comment.
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Another data store hidden inside a process is a 'ew roduct data store in the rocess 'ew roduct Re&uest process.
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:. 7rite pro4ect dictionary entries using standards given to you by your instructor/ for all the data =ows shown in the level-+ diagram in your answer to Puestion . 8ow detailed are these entries at this pointI 8ow detailed must these entries be for primitive D2DsI Again, here is an eample of a pro4ect dictionary entry for data =ow Rental $tension Re&uest, typical of many pro4ect dictionary entries?
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'ame? Rental $tension Re&uest
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De(nition? The data needed by $ntertainment Trac%er to process a re&uest by a customer to etend the rental of a product. 3ource Type? 2unction 3ource 'ame? rocess Rental $t. Re&uest Destination Type? $ternal Destination 'ame? $ntertainment Trac%er $ntity? Rental Attributes? Rental "D, @ustomer "D, Rental Date, Due Date, 'umber of days to etend.
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J. Regarding your answer to Puestion , eplain how you modeled the process that receives the 'ew roduct Re&uest data =ow. 7as this a dicult process to model on the D2DI Did you consider several alternative ways to show this processI "f so, eplain the alternatives and why you chose the representation you drew in the level-+ diagram for Puestion . "t was a challenge to model the process that receives the 'ew roduct Re&uest data =ow because it was necessary to decide on whether to include in that process the production of the list of new products re&uested for the manager. The generation of that list should be included in that process because it is very simple and closely tied to the 'ew roduct Re&uest data =ow. 3ince a D2D shows no timing, there can be a delay between entry of new re&uests and the production of the re&uest list.
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K. Loo% at your answer to Puestion and focus attention on the process for the Rental $tension Re&uest data =ow. Esing 6icrosoft Visio, draw a level-; diagram for this process based on the description of this data =ow in the case and in the following eplanation. A customer provides his or her customer number or name and a product number or title and then 6y5roadway (nds in its records the rental information for this customer#s outstanding rental of this product, including the due date. Then the customer may decide that he or she can return the item by the due date, in which case no re&uest for etension is made. "f the customer decides to etend the due date, the customer can re&uest a one-day or two-day etension, each with a di)erent fee, which will be due when the product is returned. 6y5roadway will then send a Rental $tension Re&uest transaction to $ntertainment Trac%er as if it were a point-of-sale terminal from which the same re&uest was being made. $ntertainment Trac%er may re4ect the re&uest if the customer has delin&uent fees. >nce $ntertainment Trac%er ma%es its decision, it returns a code to 6y5roadway indicating a yes or the reason for a no to the re&uest. "f the decision is no, the customer is given a message to eplain re4ection. "f yes, 6y5roadway rental data are updated to re=ect the etension, and the user is given a con(rmation message. lease refer to the Level-; D2D for the rocess Rental $tension Re&uest below.
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N. Does your answer to Puestion J necessitate any changes to your answer to Puestion I "f so, what are these changesI repare a new level-+ diagram for 6y5roadway. The answer does not necessitate changes.
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;+. "nvestigate the capabilities of 6icrosoft Visio to store and report pro4ect dictionary entries for ob4ects on data-=ow diagrams. 7hat capabilities of @A3$ tools does Visio not provideI 3tudent answers will vary.
