7/24/2019 Hoffer Mdm11e Tif 02 http://slidepdf.com/reader/full/hoffer-mdm11e-tif-02 1/25 Modern Database Management, 11e (Hoffer et al.) Chapter 2 Modeling Data in the Organization 1) Data modeling may be the most important part of the systems development process because: A) data characteristics are important in the design of programs and other systems components. B) the data in a system are generally less complex than processes and play a central role in development. C) data are less stable than processes. D) it is the easiest. Answer: A Diff: 1 age !ef: "# $opic: %ntroduction AAC&B: Analytic &'ills( se of %nformation $echnology *) $he logical representation of an organi+ation,s data is called a-n): A) database model. B) entityrelationship model. C) relationship systems design. D) database entity diagram. Answer: B Diff: 1 age !ef: "/ $opic: $he 0! odel: An 2verview AAC&B: se of %nformation $echnology 3) $he common types of entities are: A) strong entities. B) wea' entities. C) associative entities. D) all of the above. Answer: D Diff: * age !ef: "/ $opic: %ntroduction AAC&B: se of %nformation $echnology 4) %n an 0! diagram( there are 55555555 business rule-s) for every relationship. A) two B) three C) one D) none Answer: A Diff: * age !ef: "6 $opic: $he 0! odel: An 2verview AAC&B: se of %nformation $echnology 1 Copyright 7 *813 earson 0ducation( %nc. ublishing as rentice 9all
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*6) An entity that associates the instances of one or more entity types and contains attributes
specific to the relationships is called a-n):
A) associative entity.B) connecting entity.
C) intersectional entity.
D) all of the above.Answer: A
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$opic: odeling !elationshipsAAC&B: se of %nformation $echnology
&ubtopic: Basic Concepts and Definitions in !elationships
38) ;hich of the following conditions should exist if an associative entity is to be created=A) All the relationships for the participating entities are manytomany.
B) $he new associative entity has independent meaning.
C) $he new associative entity participates in independent relationships.
D) All of the above.Answer: D
Diff: * age !ef: />$opic: odeling !elationships
AAC&B: Analytic &'ills( se of %nformation $echnology
&ubtopic: Associative 0ntities
31) $he number of entity types that participate in a relationship is called the:
A) number.B) identifying characteristic.
C) degree.
D) counter.Answer: C
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$opic: odeling !elationshipsAAC&B: se of %nformation $echnology
&ubtopic: Degree of a !elationship
3*) A relationship between the instances of a single entity type is called a-n) 55555555relationship.
A) ternary
B) primaryC) binary
D) unary
Answer: DDiff: * age !ef: /6
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AAC&B: se of %nformation $echnology
&ubtopic: Degree of a !elationship
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4*) %n the figure shown below( which of the following business rules would apply=
A) 0ach vendor can supply many parts to any number of warehouses( but need not supply any
parts.
B) 0ach part must be supplied by exactly one vendor to any number of warehouses.C) 0ach warehouse can be supplied with any number of parts from more than one vendor( and
each warehouse could be supplied with no parts.
D) <one of the above.Answer: A
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$opic: odeling !elationships
AAC&B: Analytic &'ills( se of %nformation $echnology&ubtopic: A $ernary !elationship
43) A value that indicates the date or time of a data value is called a-n):A) value stamp.
B) time stamp.
C) chec'point.D) chec' counter.
Answer: B
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$opic: odeling !elationshipsAAC&B: se of %nformation $echnology
&ubtopic: odeling $imeDependent Data
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44) %n the following diagram( which answer is true=
A) 0ach employee can supervise one to many employees.
B) 0ach employee can manage many departments.
C) 0ach employee wor's in more than one department.D) All of the above.
Answer: A
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AAC&B: Analytic &'ills( se of %nformation $echnology
&ubtopic: ultiple !elationships
4") A mutually exclusive relationship is one in which:
A) an entity instance can participate in many different relationships.
B) an entity instance can participate in only one of several alternative relationships.C) an entity instance can not participate in a relationship with another entity instance.
D) none of the above.
Answer: B
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AAC&B: Analytic &'ills( se of %nformation $echnology&ubtopic: <aming and Defining !elationships
4#) ost systems developers believe that data modeling is the least important part of the systemsdevelopment process.
Answer: AE&0
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$opic: %ntroductionAAC&B: !eflective $hin'ing
4/) Data( rather than processes( are the most complex aspects of many modern informationsystems.
Answer: $!0
Diff: * age !ef: "#$opic: %ntroduction
AAC&B: !eflective $hin'ing
1"
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/>) ;hen choosing an identifier( choose one that will not change its value often.
Answer: $!0
Diff: 1 age !ef: /3$opic: odeling 0ntities and Attributes
AAC&B: se of %nformation $echnology
&ubtopic: %dentifier Attribute
/6) %t is desirable that no two attributes across all entity types have the same name.
Answer: $!0Diff: * age !ef: /3
$opic: odeling 0ntities and Attributes
AAC&B: se of %nformation $echnology
&ubtopic: <aming and Defining Attributes
>8) %t is not permissible to associate attributes with relationships.
Answer: AE&0
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AAC&B: se of %nformation $echnology&ubtopic: Basic Concepts and Definitions in !elationships
>1) A relationship instance is an association between entity instances where each relationshipinstance includes exactly one entity from each participating entity type.
68) A time stamp is a time value that is associated with a data value.
Answer: $!0
Diff: * age !ef: >>$opic: odeling $imeDependent Data
AAC&B: se of %nformation $echnology
61) !elationships represent action being ta'en using a verb phrase.
Answer: $!0
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AAC&B: se of %nformation $echnology
&ubtopic: <aming and Defining !elationships
6*) %n the figure below( the name of the relationship follows the guidelines for naming a
relationship.
Answer: AE&0Diff: * age !ef: 6*( 63
$opic: odeling !elationships
AAC&B: Analytic &'ills( se of %nformation $echnology
&ubtopic: <aming and Defining !elationships
63) 2n what premises are business rules based=
Answer: A business rules approach is based on the following:1. Because business rules are an expression of business policy( they are a core concept in an
enterprise.
*. <atural language for endusers and a data model for developers can be used to state businessrules.
Diff: * age !ef: #1( #*
$opic: odeling the !ules of the 2rgani+ation
AAC&B: !eflective $hin'ing&ubtopic: $he Business !ules aradigm
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64) ;hat are some of the guidelines for good data names of ob?ects in general=
Answer:
Data names always should:1. !elate to the business not technical characteristics. &tudent would be a good name but not
filest8*3.
*. Be meaningful so that the name tells what the ob?ect is about3. Be uniue
4. Be readable
". Be composed of words ta'en from an approved list#. Be repeatable
/. ollow a standard syntax
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$opic: odeling the !ules of the 2rgani+ationAAC&B: Analytic &'ills( !eflective $hin'ing
&ubtopic: Data <ames and Definitions
6") ;hat is the difference between an entity type and an entity instance=
Answer: An entity type is a collection of entities that share common properties. An entityinstance is a single occurrence of an entity type. &o( for example( &$D0<$ is an entity type
and Hohn &mith is an entity instance.
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$opic: odeling 0ntities and AttributesAAC&B: Analytic &'ills
&ubtopic: 0ntities
6#) 9ow is a strong entity different from a wea' entity=
Answer: A strong entity type exists independently of any other entities. A wea' entity type
depends on another -strong) entity type. ;hen an instance of the strong entity type no longerexists( any wea' entity instances which depend upon the strong entity cease to exist.
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$opic: odeling 0ntities and AttributesAAC&B: Analytic &'ills
&ubtopic: &trong @ersus ;ea' 0ntity $ypes
6/) ;hat is the difference between a simple attribute and a composite attribute=Answer: A simple attribute cannot be bro'en down into smaller components whereas a
composite attribute can be. An example of a simple attribute is last name. An example of a
composite attribute is mailing5address( which would have street( city( state and +ip code ascomponents.
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$opic: odeling 0ntities and AttributesAAC&B: Analytic &'ills
&ubtopic: Attributes
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6>) ;hat is a derived attribute( and how is it different from a stored attribute=
Answer: A derived attribute is an attribute whose value can be calculated from other related
attributes. A derived attribute is not stored in the physical table which is eventually created fromthe 0!D. A stored attribute( as its name implies( is stored as a column in the physical table.
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$opic: odeling 0ntities and AttributesAAC&B: se of %nformation $echnology
&ubtopic: &tored vs. Derived Attributes
66) ;hat is an associative entity= ;hat four conditions should exist in order to convert a
relationship to an associative entity=
Answer: An associative entity is an entity type that associates the instances of one or more entitytypes and contains attributes that are peculiar to the relationship between those entity instances.
2ften( a manytomany relationship is converted to an associative entity. $he following four
conditions should exist in order to do this:1. All the relationships for the participating entities types are many relationships.
*. $he resulting associative entity has independent meaning.
3. $he associative entity has one or more attributes other than the identifier.4. $he associative entity participates in one or more relationships independent of the entities in
188) ;hat are the three different degrees of relationship=
Answer: $he thee possible degrees are: nary -an instance of one entity is related to an instance
of the same entity type)( Binary -an entity instance of one type is related to an entity instance ofanother type) and $ernary -instance of three different types participate in a relationship).
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$opic: Basic Concepts and Definitions in !elationshipsAAC&B: Analytic &'ills( !eflective $hin'ing