CS 682 Chapter 9

True

17. In data flow diagrams, open-ended boxes represent data stores.

True

28. A decomposition diagram is also called a hierarchy chart.

False

38. An event is a logical unit of work that can be completed in parts over time.

True

46. Elementary processes are the lowest level of detail when depicted in a process model.

False Rationale: Data flows should always begin or end at a process

99. A data flow can connect an agent to a data store.

False Rationale: Another name for the data flow diagram is process model.

10. Another name for the data flow diagram is an entity relationship diagram.

False Rationale: Data flows should always begin or end at a process

100. A data flow can connect pass data directly from one data store to another data store.

True

101. A diverging data flow is one that splits into multiple data flows.

True

11. In a data flow diagram, rounded rectangles are used to represent processes.

True

12. In a data flow diagram, squares are used to represent external agents - the boundary of the system.

False Rationale: In DFDs, rounded rectangles are processes and squares are external agents.

13. In a data flow diagram, rounded rectangles are used to represent external agents - the boundary of the system.

True

14. Data flow diagrams have found new use in business process redesign.

True

15. A process is work performed on, or in response to, incoming data flows or conditions. A synonym is transform.

Answer: False Rationale: A process is work performed on, or in response to, incoming data flows or conditions.

16. Data describe work to be performed on, or in response to, incoming process flows or conditions.

False Rationale: Open-ended boxes are used for data stores and squares are used for external agents.

18. In data flow diagrams, open-ended boxes represent external agents.

True

19. In data flow diagrams, arrows represent data flows.

True

2. Logical models show what a system is or does. They are implementation independent.

True

20. A system is a process.

False Rationale: Data stores can be pulled from the entities on the entity relationship diagram.

21. If data modeling is done before process modeling, the agents on the DFD can be pulled from the entity relationship diagram.

True

22. The use of logical models reduces the risk of missing business requirements.

False Rationale: Flowcharts show the sequence of processes in an algorithm, while dEDs show the flow of data through the system

23. Data Flow Diagrams are a kind of flowchart.

False Rationale: A complex system is usually difficult to understand when viewed as a whole

24. A complex system is usually easy to understand when viewed as a whole.

True

25. Decomposition is the act of breaking a system into component subsystems, processes and subprocesses.

True

26. During decomposition, each level of abstraction reveals more or less detail as desired, about the overall system or a subset of that system

True

27. In systems analysis, decomposition allows you to partition a system into logical subsystems of processes for improved communication, analysis and design.

False Rationale: A decomposition diagram shows the top down functional decomposition and structure of a system.

29. A data flow diagram shows the top down functional decomposition and structure of a system.

False Rationale: Logical models are implementation independent.

3. Logical models show how a system is implemented.

False

30. A decomposition diagram is a tool that depicts the flow of data through a system and the work or processing performed by that system.

True

31. A hierarchy chart is another name for a decomposition diagram.

True

32. A decomposition diagram is essentially a planning tool for more detailed process models, namely, data flow diagrams.

True

33. Logical processes are work or actions that must be performed no matter how you implement the systems.

False

34. Physical processes are work or actions that must be performed no matter how you implement the systems.

False

35. Each logical process must be implemented in software.

True

37. An event is a logical unit of work that must be completed as a whole.

True

39. An event is triggered by a discrete input and is completed when the process has responded with the appropriate outputs.

False Rationale: Physical models are implementation dependent (not independent).

4. Physical models show not only what a system is or does, but also how the system is physically and technically implemented. They are implementation independent because they specify the technology.

False Rationale: An event is triggered by a discrete input and is completed when the process has responded with the appropriate outputs.

40. An event is triggered by a discrete output that is completed when the process has responded with the appropriate inputs.

True

41. Events are sometimes called transactions.

False Rationale: A function is a set of related and ongoing activities with no start or end; while an event is a unit of work that must be completed as a whole and has a start and end.

42. A function is a unit of work that must be completed as a unit or whole.

True

43. Elementary processes are discrete, detailed activities or tasks required to complete the response to an event.

False Rationale: Elementary processes are discrete, detailed activities or tasks required to complete the response to an event.

44. Elementary processes are the overall activities to be accomplished by a system.

False Rationale: Elementary processes are the lowest level of detail when depicted in a process model.

45. Elementary processes are at the highest level of detail when depicted in a process model.

True

47. Primitive processes are the lowest level of detail when depicted in a process model.

True

48. A black hole is a process that has inputs but no outputs.

False Rationale: A black hole is an incomplete specification of a process; it has only inputs but no outputs.

49. A black hole is an acceptable elementary process.

False Rationale: Physical models show not only what a system is or does, but also how the system is implemented; therefore, they are implementation dependent. Logical models are implementation independent.

5. Logical models show not only what a system is or does, but also how the system is implemented.

True

50. Gray holes can be caused by a misnamed process.

True

51. A gray hole is a process where the inputs are insufficient to produce the desired outputs.

False Rationale: A data flow is data in motion.

52. A data store represents data in motion.

True

53. A logical process can perform computations.

True

54. A logical process can make decisions.

True

55. A logical process can trigger other processes.

True

56. A logical process can use stored data to create, read, update or delete a record.

True

57. Structured English is a language and syntax, based on the relative strengths of structured programming and natural English, for specifying the underlying logic of elementary processes on process models such as data flow diagrams.

True

58. An iteration structure specifies that a set of steps should be repeated based on some stated condition.

True

59. A repetition structure specifies that a set of steps should be repeated based on some stated condition.

True

6. Process modeling is a technique for organizing and documenting the structure and flow of data through a system's processes and /or the logic, policies and procedures to be implemented by a system's processes.

Answer: False Rationale: A conditional structure specifies that a process must perform different steps under well-specified conditions. A repetition or iteration structure specifies that a set of steps should be repeated based on some stated condition.

60. A conditional structure specifies that a set of steps should be repeated based on some stated condition.

True

61. A conditional structure specifies that a process must perform different steps under well-specified conditions.

True

62. A function is a set of related and ongoing activities of the business.

True

63. A restriction of Structured English is that only strong, imperative verbs may be used.

True

64. A restriction of Structured English is that only names that have been defined in the project dictionary may be used.

False Rationale: A restriction of Structured English is that only names that have been defined in the project dictionary may be used.

65. Structured English allows the analyst to define new terms as the process is being defined.

True

66. A restriction of Structured English is that formulas should be stated clearly using appropriate mathematical notations.

True

67. Undefined adjectives and adverbs are not permitted in Structured English unless they have been clearly defined in the project dictionary.

True

68. Blocking and indentation should be used in Structured English to set off the beginning and ending of constructs to enhance readability.

False Rationale: Blocking and indentation should be used in Structured English to set off the beginning and ending of constructs to enhance readability.

69. Spacing, blocking and indentation are not important in Structured English since it is not a formal programming language.

True

7. A data flow diagram (DFD) is a tool that depicts the flow of data through a system and the work or processing performed by that system.

True

70. In Structured English, when in doubt, user readability should take priority over programmer preferences.

True

71. Structured English should be precise enough to clearly specify the required business procedure to a programmer or user. But it should not be so inflexible that you spend hours arguing over syntax.

False Rationale: Structured English should be precise enough to clearly specify the required business procedure to a programmer or user. But it should not be so inflexible that you spend hours arguing over syntax.

72. Structured English is very precise and requires a strict adherence to syntax rules so that it can be translated for specifications to programming code directly.

False Rationale: Simple condition steps can be translated into programming language as an If test

73. Simple condition steps can be translated into programming language as a For loop.

True

74. A policy is a set of rules that governs some process in the business.

True

75. Both decision tables and Structured English can describe a single elementary process.

True

76. A decision table is a tabular form of presentation that specifies a set of conditions and their corresponding actions.

False Rationale: A decision table is a tabular form of presentation that specifies a set of conditions and their corresponding actions.

77. A decision table is expressed in Structured English to facilitate the presentation of policies and processes using a single technique.

True

78. Decision tables are useful for specifying complex policies and decision-making rules.

True

79. The three components of a decision table are: condition stubs, action stubs and rules.

False Rationale: A data flow diagram (DFD) is a tool that depicts the flow of data through a system and the work or processing performed by that system. The DFD is a representation of the process model. An entity relationship diagram (ERD) is a representation of the data model.

8. An entity relationship diagram (ERD) is a tool that depicts the flow of data through a system and the work or processing performed by that system.

False Rationale: The three components of a decision table are: condition stubs, action stubs and rules.

80. The three components of a decision table are: entities, relationships and attributes.

True

81. A data flow represents an input of data to a process or the output of data from a process.

True

82. Composite data flows are used to combine similar data flows on high-level data flow diagrams to make those diagrams easier to read.

True

83. A composite data flow is a data flow that consists of other data flows.

False Rationale: A composed data flow is a data flow that consists of other data flows

84. A compound data flow is a data flow that consists of other data flows.

True

85. A data flow is composed of either actual data attributes (also called data structures) or other data flows.

True

86. The packet concept is critical to the creation of data flow diagrams. Data that should travel together should be shown as a single data flow, no matter how many physical documents or attributes are included in the data flow.

True

87. A control flow represents a condition or non-data event that triggers a process.

False Rationale: A control flow represents a condition or non-data event that triggers a process.

88. A control flow is a special data flow that has both inputs and outputs.

True

89. Data conservation requires that a data flow contain only the data that is truly needed by the receiving process.

True

9. A data flow diagram is a process model.

False Rationale: Data conservation requires that a data flow contain only the data that is truly needed by the receiving process.

90. Data conservation requires that a data flow contain the entire data entity with all its attributes that is requested by a process.

False Rationale: By ensuring that processes receive only as much data as they really need, we simplify the interface between those processes.

91. By ensuring that processes receive the entire entity and its attributes, we plan for future processing requirements to improve the implementation and maintenance of processes.

True

92. A data attribute is the smallest piece of data that has meaning to the end users and the business.

False Rationale: The definition of data attribute is the smallest piece of data that has meaning to the end users and the business. This same definition applies to both data and process models.

93. The concept of a data attribute is different when drawing data models versus process models.

False Rationale: Data structures are specific arrangements of data attributes that define the organization of a single instance of a data flow.

94. Data structures are non-specific arrangements of data that define data in a data store.

True

95. The data type for an attribute defines what class of data can be stored in that attribute.

Answer: False Rationale: The data type for an attribute defines what class of data that can be stored in an attribute, whereas the domain of an attribute defines what values an attribute can legitimately take on.

96. The domain of an attribute defines what class of data can be stored in that attribute.

True

97. The domain of an attribute defines what values an attribute can legitimately take on.

True

98. Data flows can be described in terms of the following types of data structures: a sequence or group of data attributes that occur one after another; the selection of one or more attributes from a set of attributes; and, the repetition of one or more attributes.

True

1. A model is a representation of reality