Chapter 8 Flashcards Preview

MET CS 682 > Chapter 8 > Flashcards

Flashcards in Chapter 8 Deck (107):
1

1. Data modeling is a technique for defining business requirements for a database.

Answer: True Page: 270 LOD: Easy

2

2. Data modeling is a technique for organizing and documenting a system's logical and physical models.

Answer: False Page: 270 LOD: Medium
Rationale: Data modeling is a technique for organizing and documenting a system's data.

3

3. Data modeling is sometimes called database modeling because a data model is eventually implemented as a database.

Answer: True Page: 270 LOD: Easy

4

6. An identity is a class of persons, places, objects, events, or concepts about which we need to capture and store data.

Answer: False Page: 271 LOD: Medium
Rationale: An entity is a class of persons, places, objects, events or concepts about which we need to capture and store data.

5

7. An entity instance is a single occurrence of an entity.

Answer: True Page: 272 LOD: Easy

6

8. An entity existence is a single occurrence of an entity.

Answer: False Page: 272 LOD: Easy
Rationale: An entity instance is a single occurrence of an entity.

7

9. An attribute is a descriptive property or characteristic of an entity.

Answer: True Page: 272 LOD: Easy

8

10. A compound attribute is one that actually consists of other attributes that are logically grouped together.

Answer: True Page: 272 LOD: Easy

9

11. A compound attribute is an attribute that will be expanded into a separate entity.

Answer: False Page: 272 LOD: Medium
Rationale: A compound attribute is one that actually consists of other attributes that are logically grouped together.

10

12. The data type of an attribute defines what type of data can be stored in that attribute.

Answer: True Page: 272 LOD: Easy

11

13. Example data types include: numbers, text, memo, date, time, yes/no, Boolean, value set, or image.

Answer: True Page: 272 LOD: Easy

12

16. A key is an attribute, or group of attributes, that assumes a unique value for each entity instance. It is sometimes called an identifier.

Answer: True Page: 273 LOD: Easy

13

17. A key is an attribute or group of attributes that assumes a unique value for each entity instance. It is sometimes called the domain of the attribute.

Answer: False Page: 273 LOD: Medium
Rationale: A key is an attribute, or group of attributes, that assumes a unique value for each entity instance. It is sometimes called an identifier.

14

18. A concatenated key is a group of attributes that uniquely identifies an instance of an entity.

Answer: True Page: 273 LOD: Easy

15

19. A concatenated key is also known as a composite key or a compound key.

Answer: True Page: 273 LOD: Easy

16

20. A candidate key must be a single attribute.

Answer: False Page: 274 LOD: Medium
Rationale: A candidate key may be a single attribute or a concatenated key.

17

21. A candidate key may be a single attribute or a concatenated key.

Answer: True Page: 274 LOD: Easy

18

22. A primary key is that candidate key that will most commonly be used to uniquely identify a single entity instance.

Answer: True Page: 274 LOD: Easy

19

23. An example of domain would be an attribute called grade where the values could only be A, B, C, D, E, or F.

Answer: True Page: 272 LOD: Medium

20

26. A subsetting criteria is also known as an inversion entry.

Answer: True Page: 274 LOD: Easy

21

27. A subsetting criteria is a domain of attributes whose values are limitless to allow for a variety of subsets to be constructed from a database.

Answer: False Page: 274 LOD: Medium
Rationale: A subsetting criteria is an attribute or concatenated attribute whose finite values divide all entity instances into useful subsets.

22

28. A relationship is a natural business association that exists between one or more entities.

Answer: True Page: 275 LOD: Easy

23

29. A relationship may represent an event that links the entities or merely a physical affinity that exists between the entities.

Answer: False Page: 275 LOD: Hard
Rationale: A relationship may represent an event that links the entities or merely a logical affinity that exists between the entities.

24

30. All data model relationships are unidirectional.

Answer: False Page: 275 LOD: Medium
Rationale: Relationships are bi-directional.

25

31. Because all relationships are bi-directional in an entity relationship diagram, cardinality must be defined in both directions for every relationship.

Answer: True Page: 275 LOD: Easy

26

32. Conceptually cardinality defines the minimum and maximum attributes that can be added to an entity.

Answer: False Page: 275 LOD: Medium
Rationale: Cardinality is the minimum and maximum number of occurrence of one entity that may be related to a single occurrence of the other entity.

27

33. The degree of a relationship is the number of entities that participate in the relationship.

Answer: True Page: 275 LOD: Easy

28

36. A recursive relationship is a relationship with a degree of infinity, because there is no limit to how many entities participate in the relationship.

Answer: False Page: 276 LOD: Medium
Rationale: A recursive relationship is a relationship with a degree of one (1), only one entity participates in the relationship.

29

37. A recursive relationship identifies a relationship that may exist between different instances of the same entity.

Answer: True Page: 276 LOD: Easy

30

38. A ternary relationship is a relationship among three entities.

Answer: True Page: 276 LOD: Easy

31

39. The relationship between a student entity and a curriculum entity would be classified as recursive.

Answer: False Page: 276 LOD: Easy
Rationale: A recursive relationship identifies a relationship that may exist between different instances of the same entity

32

60. During the requirements phase, the physical data model is transformed into the logical data model.

Answer: False Page: 286 LOD: Medium
Rationale: During systems design, the logical data model will be transformed into a physical data model.

33

61. Another name for the logical data model is the database schema.

Answer: False Page: 286 LOD: Medium
Rationale: Another name for the physical data model is the database schema.

34

62. The data model is metadata - that is, it is data about data.

Answer: True Page: 286 LOD: Easy

35

63. The value of a key should not change over the lifetime of each entity instance.

Answer: True Page: 292 LOD: Easy

36

66. Controls must be installed to ensure that the value of a key is valid.

Answer: True Page: 292 LOD: Easy

37

67. An intelligent key is a business code whose structure communicates data about an entity instance (such as its classification, size or other properties).

Answer: True Page: 292 LOD: Easy

38

68. The authors of your textbook recommend the use of intelligent keys since they can be quickly processed by humans without the assistance of a computer.

Answer: True Page: 292 LOD: Medium

39

69. Some experts suggest that you avoid the use of intelligent keys when designing your data model. They argue that because characteristics can change it violates the rule that the value of a key should not change over the lifetime of each entity instance.

Answer: True Page: 292 LOD: Medium

40

70. Serial codes assign sequentially generated numbers to entity instances.

Answer: True Page: 292 LOD: Easy

41

71. Alphabetic codes use finite combinations of letters (and possibly numbers) to describe entity instances.

Answer: True Page: 293 LOD: Easy

42

72. In significant position codes, each digit or group of digits describes a measurable or identifiable characteristic of the entity instance.

Answer: True Page: 293 LOD: Easy

43

73. Significant position codes are frequently used to code inventory items.

Answer: True Page: 293 LOD: Medium

44

76. Once the data model has been defined, it is trivial to identify the remaining data attributes.

Answer: False Page: 295 LOD: Medium
Rationale: It is not a trivial task to identify the remaining data attributes. To accomplish this task, it is necessary to have a thorough understanding of the data attributes for the system.

45

77. Many organizations have naming standards and approved abbreviations for data attributes.

Answer: True Page: 295 LOD: Easy

46

78. A good data model is simple.

Answer: True Page: 298 LOD: Easy

47

79. A good data model is essentially nonredundant.

Answer: True Page: 298 LOD: Easy

48

80. In a good data mode, each data attribute describes at most one entity.

Answer: False Page: 298 LOD: Medium
Rationale: Each attribute, other than foreign keys, describes at most one entity.

49

81. A good data model should be flexible and adaptable to future needs.

Answer: True Page: 298 LOD: Easy

50

82. A good data model is inflexible because it is an accurate representation of the business data requirements.

Answer: False Page: 298 LOD: Medium
Rationale: A good data model should be flexible and adaptable to future needs.

51

83. Data analysis is a process that prepares a logical model for implementation as a redundant, explicit, and finite database through a technique called generalization.

Answer: False Page: 299 LOD: Medium
Rationale: Data analysis is a process that prepares a data model for implementation as a simple, nonredundant, flexible and adaptable database through a technique called normalization.

52

86. An entity is in third normal form (3NF) if it is already in 2NF and if the values of its nonprimary key attributes are not dependent on any other nonprimary key attributes.

Answer: True Page: 299 LOD: Medium

53

87. An entity is in third normal form (3NF) if it is already in 2NF and if the values of all nonprimary key attributes are dependent on the full primary key - not just part of it.

Answer: False Page: 323 LOD: Hard
Rationale: An entity is in second normal form (2NF) if it is already in 1NF and if the values of all nonprimary key attributes are dependent on the full primary key not just part of it.

54

88. An entity is in first normal form (1NF) if the values of its nonprimary key attributes are not dependent on any other nonprimary key attributes.

Answer: False Page: 299 LOD: Hard
Rationale: An entity is in first normal form (1NF) if there are no attributes that can have more than one value for a single instance of the entity.

55

89. One form of 3NF makes sure that transitive dependencies exist in each entity.

Answer: False Page: 304 LOD: Hard
Rationale: Transitive dependency is an error that is removed by 3NF.

56

90. A data-to-location CRUD matrix is a table in which the rows indicate entities (and possible attributes); the columns indicate locations; and the cells (the intersection of the rows and columns) document level of access where C=create; R=read; U=update; and D=delete or deactivate.

Answer: True Page: 308 LOD: Easy

57

91. A data-to-location CRUD matrix is a table in which garbage values that fall outside the domain of an attribute are identified and used for data verification.

Answer: False Page: 308 LOD: Medium
Rationale: A data-to-location CRUD matrix is a table in which the rows indicate entities (and possible attributes); the columns indicate locations; and the cells (the intersection of the rows and columns) document level of access where C=create; R=read; U=update; and D=delete or deactivate.

58

92. Many nonspecific relationships can be resolved into two one-to-many relationships using an associative entity.

Answer: True Page: 280 LOD: Medium

59

93. A generalization hierarchy can be at most two levels deep.

Answer: False Page: 284 LOD: Medium
Rationale: A generalization hierarchy can be any number of levels deep. See Figure 8-11.

60

96. A data type:
A) defines what type of data can be stored in an attribute.
B) could be text, number, date, time, yes/no, value set or image.
C) consists of compound attributes.
D) both (A) and (B)
E) none of these

Answer: D Page: 272 LOD: Medium

61

97. What defines what values an attribute can legitimately take on?
A) realm
B) entity
C) relationship
D) domain
E) none of these

Answer: D Page: 272 LOD: Medium

62

98. The value that is recorded in an attribute if a user does not specify one is known as the:
A) domain
B) key
C) default value
D) data type
E) none of these

Answer: C Page: 273 LOD: Medium

63

99. An attribute or group of attributes that assumes a unique value for each entity instance is a:
A) domain
B) key
C) default value
D) data type
E) none of these

Answer: B Page: 273 LOD: Medium

64

100. Any candidate key that is not selected to become the primary key is called:
A) the entity key
B) the concatenated key
C) the subsetting key
D) the domain key
E) the alternate key

Answer: E Page: 274 LOD: Medium

65

101. If an employee entity had both an EmployeeID attribute and a Social Security Number attribute, the one that was not used as the primary key would be called a(n):
A) entity key
B) concatenated key
C) alternate key
D) candidate key
E) all of these

Answer: C Page: 274 LOD: Medium

66

102. An attribute or concatenated attribute whose values divide all entity instances into useful subsets is known as:
A) primary criteria
B) secondary criteria
C) alternate criteria
D) subsetting criteria
E) none of these

Answer: D Page: 274 LOD: Medium

67

103. What defines the minimum and maximum number of occurrences of one entity that may be related to a single occurrence of the other entity?
A) domain
B) concatenation
C) associative entity
D) cardinality
E) none of these

Answer: D Page: 275 LOD: Medium

68

106. An entity that inherits its primary key from more than one entity is called a(n):
A) associative entity
B) concatenated entity
C) ternary
D) many-to-many cardinality
E) none of these

Answer: A Page: 276 LOD: Medium

69

107. When a parent entity contributes its primary key to become part of the primary key of the child entity, the relationship is known as:
A) primary
B) associative
C) nonidentifying
D) identifying
E) none of these

Answer: D Page: 279 LOD: Medium

70

108. A relationship where many instances of one entity can be associated with many instances of another entity is known as:
A) ternary
B) many-to-many
C) nonspecific
D) B and C
E) none of these

Answer: D Page: 279 LOD: Medium

71

109. A technique wherein attributes that are common to several types of an entity are grouped into their own entity called a supertype is called:
A) normalization
B) generalization
C) concatenation
D) compound data type
E) none of these

Answer: B Page: 283 LOD: Medium

72

110. An entity whose instances store attributes that are common to one or more entities is a(n):
A) supertype
B) subtypes
C) compound type
D) default type
E) none of these

Answer: A Page: 283 LOD: Medium

73

111. The data model for a single information system is usually called:
A) the enterprise data model
B) the logical data model
C) the physical data model
D) the application data model
E) none of these

Answer: D Page: 285 LOD: Medium

74

112. The problem analysis phase model that includes only entities and relationships but no attributes is known as:
A) the enterprise data model
B) the application data model
C) the context data model
D) does not exist, all data models must have attributes
E) none of these

Answer: C Page: 285 LOD: Medium

75

113. During requirements analysis, what order of model development is used to arrive at the logical data model?
A) context data model; fully attributed data model; key-based data model; normalized data model
B) normalized data model; context data model; fully attributed data model; key-based data model
C) normalized data model; key-based data model; fully attributed data model; context data model
D) context data model; key-based data model; fully attributed data model; normalized data model
E) none of these

Answer: D Page: 285-286 LOD: Medium

76

116. A key value whose structure communicates data about an entity instance:
A) is known as an intelligent key.
B) should be avoided (suggested by the authors of your book).
C) is randomly assigned.
D) can only use alphabetic codes.
E) all of these

Answer: A Page: 292 LOD: Medium

77

117. A code that assigns sequentially generated numbers to entity instances is known as:
A) a serial code
B) a sequential code
C) an alphabetic code
D) a significant position code
E) none of these

Answer: A Page: 292 LOD: Medium

78

118. A code that uses blocks of numbers that are divided into groups that have some business meaning is known as a:
A) serial code
B) hierarchical code
C) significant position code
D) block code
E) none of these

Answer: D Page: 293 LOD: Medium

79

119. A code that provides a top-down interpretation for an entity instance is known as:
A) a serial code
B) a structured code
C) a significant position code
D) a hierarchical code
E) none of these

Answer: D Page: 293 LOD: Medium

80

120. Which of the following is NOT a guideline for creating a business coding scheme?
A) Codes should be expandable to accommodate growth.
B) The full code must result in redundant values for entities.
C) Codes should be large enough to describe distinguishing characteristics, but small enough to be interpreted by a person without a computer.
D) Codes should be convenient.
E) All of these

Answer: B Page: 293 LOD: Medium

81

121. Which of the following is a criteria for making a good data model?
A) A good data model is simple.
B) A good data model is essentially nonredundant.
C) A good data model should be flexible and adaptable to future needs.
D) Each data attribute should describe at most one entity.
E) All of these.

Answer: E Page: 298 LOD: Easy

82

122. The process that prepares a data model for implementation as a simple, nonredundant, flexible and adaptable database is known as:
A) process analysis
B) requirements analysis
C) data analysis
D) generalization
E) none of these

Answer: C Page: 299 LOD: Medium

83

123. The process that prepares a data model for implementation as a database is known as:
A) contextualization
B) normalization
C) data analysis
D) both normalization and data analysis
E) none of these

Answer: D Page: 299 LOD: Medium

84

126. In the relationship between US cities and US states, the state entity would be:
A) the child
B) the parent
C) nonspecific
D) subtype
E) supertype

Answer: B Page: 277 LOD: Medium

85

127. An entity is in third normal form if:
A) all the values of primary keys are independent on the nonprimary keys.
B) values of nonprimary key attributes are not dependent on any other nonprimary key attributes.
C) values of its nonprimary key attributes are dependent on any other nonprimary key attributes.
D) you add additional nonkey attributes that are dependent on other nonkey attributes.
E) none of these.

Answer: B Page: 299 LOD: Medium

86

128. Which normal form deals with transitive dependencies?
A) 1NF
B) 2NF
C) 3NF
D) all of these
E) none of these

Answer: C Page: 304 LOD: Medium

87

129. When a nonkey attribute is dependent on another nonkey attribute (other than by derivation) is known as:
A) an associative dependency
B) a concatenation dependency
C) a transitive dependency
D) a derived dependency
E) none of these

Answer: C Page: 304 LOD: Medium

88

130. A table in which rows indicate entities (and possible attributes) and the columns indicate locations, and the cells indicate the document level of access including create, read, update or delete is known as:
A) an entity relationship table
B) a transitive dependency table
C) a data-to-location CRUD matrix
D) a decision table
E) none of these

Answer: C Page: 308 LOD: Medium

89

131. An entity relationship diagram:
A) is used in data modeling.
B) depicts data in terms of entities and relationships.
C) identifies the cardinality of a relationship.
D) makes clear the degree of a relationship.
E) all of these

Answer: E Page: 271 LOD: Easy

90

132. An entity:
A) is something about which the business needs to store data.
B) is a class of persons, places, objects, events or concepts about which we need to capture and store data.
C) can have many instances.
D) can have many attributes.
E) all of these

Answer: E Page: 271-272 LOD: Easy

91

133. Every student resides in 0 or 1 dorm. This is an example of:
A) domain
B) default
C) degree
D) cardinality
E) nonspecific relationship

Answer: D Page: 275 LOD: Medium

92

136. A(n) ________________________ is a piece of data that we want to store about each instance of a given entity.

Answer: attribute Page: 272 LOD: Medium

93

137. The three properties of an attribute are: ___________________________, _______________________, and _____________________________.

Answer: data type, domain and default Page: 272-273 LOD: Hard

94

138. The ___________________________ defines what values an attribute can legitimately take.

Answer: domain Page: 272 LOD: Medium

95

139. The ________________________________ is the value that will be recorded for an attribute if a user does not specify one.

Answer: Default value Page: 273 LOD: Medium

96

160. A(n) ______________________ data model contains only entities and relationships, but no attributes.

Answer: context Page: 285 LOD: Medium

97

161. _________________________ is data about the business's data.

Answer: Metadata Page: 286 LOD: Medium

98

162. __________________ codes assign sequentially generated numbers to entity instances.

Answer: Serial Page: 292 LOD: Hard

99

163. __________________ codes assign numbers that have been divided into groups based on some business meaning.

Answer: Block Page: 293 LOD: Hard

100

166. __________________________ codes provide a top-down interpretation for an entity instance.

Answer: Hierarchical Page: 293 LOD: Hard

101

167. ____________________________ is a process that prepares a data model for implementation as a simple, nonredundant, flexible and adaptable database.

Answer: Data analysis or normalization Page: 299 LOD: Medium

102

168. _________________________ is a data analysis technique that organizes data attributes such that they are grouped to form nonredundant, stable, flexible, and adaptive entities.

Answer: Normalization Page: 299 LOD: Medium

103

169. ________________________ attributes are those whose values can either be calculated from other attributes or derived through logic from the values of other attributes.

Answer: Derived Page: 302 LOD: Medium

104

170. _____________________________ is a technique for organizing and documenting a system's data.

Answer: Data Modeling Page: 270 LOD: Medium

105

171. Data modeling is sometimes called __________________________________ because a data model is usually implemented as a database.

Answer: database modeling Page: 270 LOD: Medium

106

172. A(n) _________________________ is something that the business needs to store data.

Answer: Entity Page: 271 LOD: Medium

107

173. Categories of _____________________ include: persons, places, objects, events or concepts.

Answer: entities Page: 271 LOD: Medium