chapter 4

Chapter 4—Documenting Information Systems

TRUE/FALSE

1. In a DFD, a bubble symbol shown below depicts a function or a process within which incoming data flows are transformed into outgoing data flows.

ANS: T

2. In a DFD, a square represents an internal entity

ANS: F

3. In a DFD, two parallel lines represent the data store symbol

ANS: T

4. The following symbol represents general purpose input-output

ANS: F

5. The following symbol represents a manual process

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ANS: T

6. The following symbol represents a disk

ANS: F

7. The following symbol represents paper filing.

ANS: T

8. The following symbol represents a computer process

ANS: T

9. In a DFD, an external entity symbol portrays a source or a destination (sink) outside the system.

ANS: T

10. A context diagram is the top-level diagram in a series of data flow diagrams representing an information system and it shows the flows into and out of the system of interest and into and out of external entities.

ANS: T

11. Internal entities are those persons, places, or things outside our system that send data to, or receive data from, our system.

ANS: F

12. An external entity is a person, place, or thing within the system that transforms data.

ANS: F

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13. A physical data flow diagram uses bubbles to specify where, how, and by whom a system's processes are accomplished.

ANS: T

14. When the context diagram and the level 0 diagram reflect the equivalent external data flows, the two diagrams are said to be balanced.

ANS: T

15. The successive subdivision, or "exploding," of logical DFDs is called bottom up partitioning.

ANS: F

16. A systems flowchart is a graphical representation of both the physical and logical features of an information system.

ANS: T

17. Processes that handle other-than-normal situations are called exception routines.

ANS: T

18. Information processing activities including retrieving data from a file, transforming data, or filing data.

ANS: T

19. An acceptance stub is a data flow that leaves a bubble but does not go to any other bubble or file and indicates processing that is performed in other than normal situations.

ANS: F

20. In an enterprise system, we would have one data store/disk symbol that would be labeled “enterprise database” instead of two or more data store symbols.

ANS: T

21. When we convert to an enterprise system, reengineered processes often result from the installation and can cause changes throughout the systems flowcharts.

ANS: T

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MULTIPLE CHOICE

1. A symbol used in data flow diagrams to depict an entity or process within which incoming data flows are transformed into outgoing data flows is a(n):a. data flow symbolb. external entity symbolc. bubble symbold. file symbol

ANS: C

2. A data flow diagram could contain each of the following symbols except:a. a bubble or circleb. a non-square rectanglec. a squared. a curved line with arrow head

ANS: B

3. Which of the following symbols is represented by two parallel lines?a. data flow symbolb. external entity symbolc. sink symbold. file symbol

ANS: D

4. Which symbol portrays a source or destination of data outside the system?a. data flow symbolb. external entity symbolc. bubble symbold. file symbol

ANS: B

5. Those entities which perform no information processing activities for the system are called:a. external entitiesb. internal entitiesc. boundary entitiesd. environmental entities

ANS: A

6. Which symbol can be either an entity or a process depending on the type of DFD?a. bubble symbolb. external entity symbolc. data flow symbold. file symbol

ANS: A


7. Which of the following is the least detailed of the data flow diagrams?a. logical data flow diagramb. systems flowchartc. context diagramd. physical data flow diagram

ANS: C

8. In a physical data flow diagram, a bubble or circle could be used to specify each of the following except:a. where a process is performedb. how a process is performedc. by whom a process is performedd. what process is performed

ANS: D

9. Which type of data flow diagram specifies where, how, and by whom a system's processes are performed?a. context diagramb. physical data flow diagramc. logical data flow diagramd. systems flowchart

ANS: B

10. A person, place, or thing within a system that transforms data is called:a. external entityb. relevant environmentc. internal entityd. Boundary

ANS: C

11. Which data flow diagram shows a system's processes and the flow of data into and out of the processes?a. context diagramb. physical data flow diagramc. systems flowchartd. logical data flow diagram

ANS: D

12. Data flow labels in context diagrams usually describe:a. what the data are (physical labels)b. the nature of the data (logical labels)c. to whom the data are being transmitted (identity labels)d. where the data are being sent (directional labels)

ANS: B

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13. In which of the following DFDs does the bubble symbol represent a process and not the entire system?a. context diagramb. physical data flow diagramc. logical data flow diagramd. systems flowchart

ANS: C

14. In a logical DFD for a cash receipts system, each of the following labels might appear in a bubble except:a. Cashierb. capture cash receiptsc. endorse checksd. update master files

ANS: A

15. The data flows in a logical flow diagram show:a. how the data are transmittedb. where the data are transmittedc. the nature of the data being transmittedd. who receives the transmitted data

ANS: C

16. When two data flow diagrams have equivalent external data flows, we say that the two data flow diagrams are:a. Congruentb. Similarc. Balancedd. Equal

ANS: C

17. A process in which successive layers of data flow diagrams are constructed by "exploding" the bubbles on a less detailed DFD to show more detailed data flows is called:a. top-down partitioningb. serial expansionc. balanced constructiond. expanded data flows

ANS: A

18. Which of the following is statements related to the construction of data flow diagrams is false?a. The level 0 diagram is the next level down from the context diagram.b. If the level 0 diagram has one arrow going into bubble number 1.0 and two arrows leaving

bubble number 1.0, then diagram 1.0 will show one arrow entering and two arrows leaving.

c. Sources and destinations are depicted by parallel horizontal lines, between which the name of the entity is shown.

d. Arrows represent a pathway for data.

ANS: C


19. When constructing data flow diagrams:a. as a bubble expands from level 0 to level 1 and then to level 2, the numbering of the

bubbles goes from 0.1 to 1.1 to 2.1, respectivelyb. external entities do not appear below the level 0 diagramsc. exceptions are always presentedd. data flow symbols only appear in context diagrams or level 0 DFDs

ANS: B

20. A systems flowchart varies from a data flow diagram because it:a. only represents the information systemb. only represents the operations systemc. represents both the information system and the operations systemd. represents the information system, the operations system, and the management system

ANS: D

21. Information processing activities include:a. only automated activitiesb. activities that retrieve, transform, and file datac. the sending of data between entitiesd. operational activities

ANS: B

22. Why do auditors and systems analysts use systems documentation?a. to understand, explain, and improve complex systemsb. to only provide justification to management for systems investmentsc. to reduce the number and amount of external entitiesd. to eliminate evidence to be collected

ANS: A

23. On a systems flowchart, computer processing is represented by a:a. Squareb. Trapezoidc. Rectangled. Parallelogram

ANS: C

24. On a systems flowchart, a paper file is represented by a:a. Triangleb. Cylinderc. Rectangled. Pentagon

ANS: A

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25. On a systems flowchart, a dashed line with an arrow going from one symbol such as that for a magnetic tape to a second copy of that same symbol indicates:a. only some data are passed between the two devicesb. the two devices operate simultaneously in parallelc. documents but not electronic data flow between the two devicesd. one copy is the original which is to be replaced after updating by the other copy

ANS: D

26. Which of the following systems flowcharting symbol descriptions is incorrect?

a. Diskb. computer processc. manual processd. CRT display

ANS: C

27. Which of the following systems flowcharting symbols descriptions is incorrect?

a. Tapeb. on-page connectorc. start/stopd. paper file

ANS: D


28. Which of the following systems flowcharting symbols descriptions is incorrect?

a. general purpose input-outputb. manual operationc. multiple-page documentd. punched card

ANS: D

29. How many bubbles are included in a correctly drawn context diagram?a. Zerob. Onec. Threed. more than one but no more than are necessary to model the system

ANS: B

30. An information processing activity could be any of the following except:a. sending or receiving datab. preparing documentsc. data entryd. verifying data

ANS: A

31. In drawing a context diagram, we should include:a. only that portion of a narrative description which relates to data transformationb. only that portion of a narrative description which describes external entitiesc. all activity described in a system narratived. only that portion of a narrative description which describes data flows

ANS: C

32. How many bubbles should be used in a logical data flow diagram?a. Oneb. three to fivec. five to sevend. as many as needed but no more than five

ANS: C

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33. On a logical data flow diagram, data flows:a. always go from a higher-numbered to a lower-numbered bubbleb. never go from a higher-numbered to a lower-numbered bubblec. can go in either direction as neededd. must go from a bubble to a box

ANS: B

34. In general, a process bubble appearing in a level 0 data flow diagram reflects:a. the sending of a document from one department to anotherb. the filing of a documentc. the updating of a filed. the transformation of data

ANS: D

35. All of the following are "guidelines" for grouping activities in a level 0 DFD except:a. group activities if they occur in the same place and at the same timeb. group activities if they are performed by the same entity but at different timesc. group activities if they occur at the same time but in different placesd. group activities in order to eliminate single-activity bubbles wherever possible

ANS: B

36. When a transaction cannot be processed in a routine fashion because of an error or other processing problems, the transaction must be handled by a(n):a. rejection routineb. change reportc. exception and summary reportd. exception routine

ANS: D

37. The following is a jumbled list of the activities suggested in this text for drafting data flow diagrams for an existing system:

I. Prepare a table of entities and activities.II. Prepare a chronologically sorted table of entities and activities.

III. Draw a physical data flow diagram.IV. Draw a logical data flow diagram.V. Draw a context diagram.

The best sequence for undertaking these activities is:a. I, II, V, III, IVb. I, V, III, II, IVc. II, I, III, V, IVd. II, IV, III, I, V

ANS: B


38. Examine the following context diagram and the related level 0 logical data flow diagram. Which of the following statements is true?

39.

a. The data flow diagrams are prepared correctly.b. A context diagram must have a least two external entities.c. The logical data flow diagram is not balanced.d. The logical data flow diagram must have 5 to 7 processes.

ANS: C

39. Which statement concerning the following 1.0 data flow diagram is true?

a. The data flow diagram follows DFD guidelines.b. An arrow should never leave a bubble with no destination.c. Data should only flow from a data store.d. Level 1.0 diagrams should show the external entities.

ANS: A

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40. Which of the following segments violates guidelines for creating systems flowcharts?

a. Segment a.b. Segment b.c. Segment c.d. Segment d.

ANS: A

41. The following systems flowchart describes how a data entry clerk key enters data on a source document into business event data. Which statement describes whether the systems flowchart was created properly?

a. The systems flowchart was created properly.b. The arrow between the computer process and the data store should be bi-directional.c. The computer process should be shown in the computer column.d. The second symbol in the data entry clerk column should be a square.

ANS: C


42. The following systems flowchart describes how a manager queries a data store to view information on a computer screen. Which statement describes whether the systems flowchart was created properly?

a. The systems flowchart was created properly.b. Only a single direction arrow should flow from the data store symbol to the process query

symbol.c. The input query symbol should be a square.d. The input query symbol should be in the computer column.

ANS: B

43. The following systems flowchart describes how a user enters business event data from a source document to update master file data. Which statement describes whether the systems flowchart was created properly?

a. The systems flowchart was created properly.b. Only a single disk must be used to represent the master data.c. The every day symbol should be connected with a solid line.d. The data flows should move from the upper-left to lower-right corners of the systems

flowchart.

ANS: D

44. The flow of processes on a system flowchart is from:a. upper left to lower rightb. upper right to lower leftc. right to left either upper or lower cornersd. left to right either upper or lower corners

ANS: A

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COMPLETION

1. In a DFD, a(n) ____________________ depicts a function or a process within which incoming data flows are transformed into outgoing data flows.

ANS: bubble symbol

2. In a DFD, a(n) ____________________ represents a pathway for data.

ANS: data flow symbol

3. A(n) ____________________ is an external entity on a DFD that receives data from the system.

ANS: destination (sink)

4. A(n) ____________________ is an external entity on a DFD that sends data from outside the system.

ANS: source

5. In a DFD, a(n) ____________________ portrays a source or a destination (sink) outside the system.

ANS: external entity symbol

6. A(n) ____________________ is the top-level diagram in a series of ____________________ diagrams representing an information system, and it shows the flows into and out of the system of interest and into and out of external entities.

ANS:context diagramdata flow

7. ____________________ are those persons, places, or things outside our system that send data to, or receive data from, our system.

ANS: External entities

8. A(n) ____________________ is a person, place, or thing within the system that transforms data.

ANS: internal entity

9. A(n) ____________________ uses bubbles to specify where, how, and by whom a system's processes are accomplished.

ANS: physical data flow diagram

10. A(n) ____________________ DFD depicts what tasks the system performs rather than how, where, or by whom they are performed.

ANS: logical


11. When the context diagram and the level 0 diagram reflect the equivalent external data flows, the two diagrams are said to be ____________________.

ANS: balanced

12. The successive subdivision, or "exploding," of logical DFDs is called ____________________.

ANS: top-down partitioning

13. A(n) ____________________ is a graphical representation of both the physical and logical features of an information system.

ANS: systems flowchart

14. A(n) ____________________ originates, transforms, files, or receives data.

ANS: activity

15. ____________________ activities include retrieving data from a file, transforming data, or filing data.

ANS: Information processing

16. Processes that handle other-than-normal situations are called ____________________ or ____________________ routines.

ANS:exceptionerror

17. A(n) ____________________ is a data flow that leaves a bubble but does not go to any other bubble or file and indicates processing that is performed in other-than-normal situations.

ANS: reject stub

18. In a(n) __________ system, we use a central database for the business processes.

ANS: enterprise

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PROBLEM

1. Figure TB-4.1 is a "generic" level 0 data flow diagram, taken from Figure 4.5 in the text.

Required:

Using good DFD construction techniques, draw a diagram to explode bubble 3.0 to its next lower level. Diagram 3.0 should contain three processes, appropriately numbered, and should contain the following data flows in addition to those in the level 0 diagram (see NOTE):

a. Flow H runs from the first process to the second.b. Flow I runs from the first process to the third.c. Flows J and K run from the second process to the third.

NOTE: Assume that the flows shown in the level 0 diagram affect diagram 3.0 as follows:

1. Flow D runs to the first process in diagram 3.0.2. Flow B runs from the third process in diagram 3.0.3. The data flow running from the data store runs to the second process in diagram 3.0.


ANS:

2. Figure TB-4.3 shows a context diagram a cash sales system. The diagram intentionally violates several of the guidelines and other techniques presented in the text for drawing DFDs.

Required:

Identify as many of the errors in DFD construction as you can. In the diagram, place consecutive numbers (each in a circle) next to the points at which the errors exist. On your solution sheet, list the numbers and write a one- to two-sentence description of each error and what the correct procedure should be. Error 1 is provided as an example of how to construct the solution.

Error Error Description1 Data flows should not connect two external entities. Depending on the extent of the

system being analyzed, either the mail room or the bank entity should be eliminated [or be brought (documented) within the system].

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ANS:INSTRUCTOR NOTE: You may wish to modify the requirement in one of two ways: (1) Have the students redraw the diagrams instead of describing the errors or (2) limit the number of errors required in the solution to something less than the entire population.

(Figure TB-4.4, an annotated version of Figure TB-4.3, shows the location of each error.)

Error Error Description2 When multiple entities operate identically, one box can represent all. Eliminate all but

one customer box and label it "Cash customer."3 A context diagram should have only one bubble. Since the problem states that we are

analyzing a cash sales system, eliminate the first bubble.4 In the context diagram and level 0 diagram, logical rather than physical labels should

be used. Eliminate the reference to Form S92.5 The symbols used for the sales transaction event data file is incorrect. In a DFD, the

file symbol is a pair of parallel, horizontal lines.


3. Figure TB-4.5 shows a level 0 logical data flow diagram for a billing system. The logical data flow diagram intentionally violates several of the guidelines and other techniques presented in the text for drawing DFDs.

Required:

Identify as many of the errors in the logical DFD construction as you can. In the logical DFD, place consecutive numbers (each in a circle) next to the points at which the errors exist. On your solution sheet, list the numbers and write a one- to two-sentence description of each error and what the correct procedure should be. If an error occurs in more than one place, mark each occurrence of the error. Error 1 is provided as an example of how to construct the solution.

Error Error Description1 A data flow to an external entity should describe the document. After recording the

sale, a total of the sales and the sales invoice (copy 3) may be sent to the accounts receivable department.

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ANS:INSTRUCTOR NOTE: You may wish to modify the requirement in one of two ways: (1) Have the students redraw the diagram instead of describing the errors or (2) limit the number of errors required in the solution to something less than the entire population.

(Figure TB-4.6, an annotated version of the logical data flow diagram in Figure TB-4.5, shows the location of each error.)


Error Error Description2 The bubbles in the level 0 DFD are numbered incorrectly. They should be numbered

1.0, 2.0, and 3.0. 3 The label in the first bubble is a noun, referring to a physical entity. In a logical DFD,

the process labels should contain verbs describing what is done. Change the label to say something like "Prepare sales invoice."

4 In a logical DFD, there can be no backward flows. Either the recorded sales invoice flow should be eliminated, or it should go to a subsequent process bubble for action, or to a file of sales invoices.

5 The symbols used for the price list, and inventory master data are incorrect. In a DFD, the file symbol is a pair of parallel, horizontal lines.

6 Reject stubs should appear only in lower-level DFDs. Eliminate the reject stub from the level 0 diagram.

7 The data flow should be from the 1.0 bubble to the customer8 Instructor Note:

You could also include number 8 at three points. Remove “original”, “copy 2”, and “copy 3” from the sales invoice labels since they are physical details and do not normally belong in a logical DFD.

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4. Figure TB-4.7 shows several systems flowchart routines that intentionally violate good flowchart construction procedures.

Required:

Redraw each of the routines so that they conform to the guidelines and other techniques presented in the text for drawing systems flowcharts. HINT: Be alert to the description of each routine; the descriptions should govern your solution.

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ANS:INSTRUCTOR NOTE: You may wish to modify the requirement in one of two ways: (1) Have the students describe the violations instead of redrawing the flowchart segments or (2) limit the number of drawings required in the solution to only certain of the routines in Figure TB-4.7

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Sales Event Data

AR master file

Update AR

Master data

Data Processing

Solution to Part F

5. The following narrative describes Aegis Company's billing procedures:

Each evening the shipping department at Aegis Company forwards, to the billing department, copy 2 of all shipping notices for goods shipped to customers that day. The next day a billing clerk starts the billing process by obtaining unit sales prices from a price list book and noting the prices on the shipping notice. He then types a three-part invoice for each shipment, mails the original (copy 1) to the customer, and files copy 2 by customer name. From invoice copy 3, the clerk prepares a batch total, staples the total to the batch of invoices, and sends the batch to the data processing department.

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In data processing, a data control clerk first enters the invoice batch total in a control log. Then a data entry clerk keys each invoice on a key-to-disk machine. The disk that is produced by the keying operation is sorted in customer account number order using a computer sort utility. At 5:00 p.m. each evening, the invoice event data is run, together with the previous day's accounts receivable master data, to produce an updated master data. The update run also generates a daily summary report which is compared with the batch control log total. If the totals agree (see NOTE), the report is stapled to the batch of invoices, and the package is filed by date.

NOTE: Exception routines are beyond the narrative's scope.

Required:

a. Prepare a table of entities and activities.b. Prepare a context diagram.c. Prepare a physical data flow diagram.

ANS:INSTRUCTOR NOTE: This problem describes the same system used in Problem 4-6. This problem requires students to prepare selected components of systems documentation. In contrast, Instructors wishing to focus on the creation of data flow diagrams can provide their students with the solution to part a.

a. Table of Entities and Activities

Entities ActivitiesShipping department 1. Forwards copy 2 of shipping notices to billing

department

Billing clerk 2. Obtains unit sales prices from price list book

3. Notes sales prices on shipping notices4. Types a three-part invoice5. Mails original invoice to the customer6. Files copy 2 of the invoice by customer name7. Prepares a batch total of the invoices8. Staples the batch total to invoice (copy 3)

9. Sends the batch to data processing

Customer

Data control clerk 10. Enters batch total in control log11. Compares daily summary report with control log

total12. Staples daily summary report to batch of invoices13. Files the package of invoices, batch total, and

summary report


Data entry clerk(data preparation) 14. Keys each invoice on a key-to-disk machine

Computer 15. Sorts the invoice business event data16. Runs the invoice events data and previous day's

accounts receivable master data17. Updates the accounts receivable master data18. Generates a daily summary report

b. See Figure TB-4.8.

c. See Figure TB-4.9.

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6. Each evening the shipping department at Aegis Company forwards, to the billing department, copy 2 of all shipping notices for goods shipped to customers that day. The next day a billing clerk starts the billing process by obtaining unit sales prices from a price list book and noting the prices on the shipping notice. He then types a three-part invoice for each shipment, mails the original (copy 1) to the customer, and files copy 2 by customer name. From invoice copy 3, the clerk prepares a batch total, staples the total to the batch of invoices, and sends the batch to the data processing department.

In data processing, a data control clerk first enters the invoice batch total in a control log. Then a data entry clerk keys each invoice on a key-to-disk machine. The disk that is produced by the keying operation is sorted in customer account number order using a computer sort utility. At 5:00 p.m. each evening, the invoice event data is run, together with the previous day's accounts receivable master data, to produce an updated master data. The update run also generates a daily summary report which is compared with the batch control log total. If the totals agree (see NOTE), the report is stapled to the batch of invoices, and the package is filed by date.


NOTE: Exception routines are beyond the narrative's scope.

Required:

a. Prepare a chronologically sorted table of entities and activities. Indicate on this table the groupings--bubble numbers and bubble titles--to be used in preparing the level 0 logical data flow diagram.

b. Prepare a logical data flow diagram (level 0 only). The context diagram of this billing system shows two external entities: shipping department and customers.

c. Prepare a systems flowchart.

ANS:INSTRUCTOR NOTE: This problem describes the same system used in Problem 4-4. These problems require students to prepare selected components of systems documentation. In contrast, Problem 4-6 is a comprehensive problem that requires students to originate all systems documentation. Instructors wishing to focus on the creation of data flow diagrams and systems flowcharts can provide their students with the solution to part a.

a. Chronologically Sorted Table of Entities and Activities

Entities ActivitiesBilling clerk 1. Obtains unit sales prices from price list book

2. Notes sales prices on shipping notices3. Types a three-part invoice4. Files copy 2 of the invoice5. Prepares a batch total of the invoices6. Staples the batch total to invoice copies (copy 3)

Data control clerk 7. Enters batch total in control log

Data entry clerk 8. Keys each invoice on a key-to-disk machine

Computer 9. Sorts the invoice events data10. Runs the invoice events data and previous day's

accounts receivable master data11. Updates the accounts receivable master data12. Generates a daily summary report

Data control clerk 13. Compares daily summary report to control log total14. Staples daily summary report to batch of invoices15. Files the package of invoices, batch total and

summary report

b. See Figure TB-4.10.

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c. See Figure TB-4.11.


7. Figure TB-4.16 contains 14 symbols used in constructing DFDs or system flowcharts. Each symbol has been assigned a capital letter (A through N) for identification in this problem. The following is a list of 14 DFD or flowcharting symbols:

1. File (in a DFD) 2. Process (in a DFD)

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3. External entity (in a DFD) 4. Document (or output or report) 5. Manual keying of inputs 6. Computer process 7. Manual process 8. CRT display 9. Disk file10. Paper file11. Off-page connector12. Start/stop 13. Annotation14. Batch total

Required:

Match each symbol to its corresponding description by writing the description number below the each symbol.

ANS:

1. G2. I3. E4. N5. L6. C7. A8. B9. M10. D11. J12. H13. K14. F

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Documents

aegis company

input query

updated master

documenting

computer sort

billing clerk

data control

prepare selected