Database Processing-Chapter 5
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100 terms
Terms | Definitions |
|---|---|
 (T or F) 1) A data model is a plan for a database design. | TRUE Diff: 1 Page Ref: 145 |
| (T or F) 2) An entity is something that users want to track. | TRUE Diff: 1 Page Ref: 145 |
| (T or F) 3) Entities of a given type are grouped into entity classes. | TRUE Diff: 1 Page Ref: 145 |
| (T or F) 4) An entity class is described by the structure of the entities in that class. | TRUE Diff: 2 Page Ref: 145 |
| (T or F) 5) An entity instance of an entity class is the representation of a particular entity and is described by the values of the attributes of the entity. | TRUE Diff: 3 Page Ref: 145-146 |
| (T or F) 6) In E-R modeling, an attribute describes the characteristics of an entity. | TRUE Diff: 1 Page Ref: 146 |
| (T or F) 7) In E-R modeling, entities within an entity class may have different attributes. | FALSE Diff: 1 Page Ref: 146 |
| (T or F) 8) An identifier of an entity instance must consist of one and only one attribute. | FALSE Diff: 1 Page Ref: 146-147 |
| (T or F) 9) A "composite identifier" is defined as a composite attribute that is an identifier. | FALSE Diff: 3 Page Ref: 146-147 |
| (T or F) 10) An identifier serves the same role for a table that a key does for an entity. | FALSE Diff: 2 Page Ref: 147 |
| (T or F) 11) E-R modeling recognizes both relationship classes and relationship instances. | TRUE Diff: 1 Page Ref: 147 |
| (T or F) 12) In today's E-R models, attributes of relationships are still used. | FALSE Diff: 2 Page Ref: 147 |
| (T or F) 13) A single relationship class involves only one entity class. | FALSE Diff: 3 Page Ref: 147 |
| (T or F) 14) A binary relationship is a relationship based on numerical entity instance identifiers. | FALSE Diff: 2 Page Ref: 148 |
| 15) The degree of a relationship is expressed as the relationship's maximum cardinality. (T or F) | FALSE Diff: 3 Page Ref: 148-150 |
| (T or F) 16) When transforming a data model into a relational design, relationships of all degrees are treated as combinations of binary relationships. | TRUE Diff: 2 Page Ref: 148 |
| (T or F) 17) The principle difference between an entity and a table is that you can express a relationship between entities without using foreign keys. | TRUE Diff: 2 Page Ref: 148 |
| (T or F) 18) When designing a database, first identify the entities, then determine the attributes, and finally create the relationships. | FALSE Diff: 3 Page Ref: 148 |
| (T or F) 19) Relationships are classified by their cardinality. | TRUE Diff: 1 Page Ref: 149 |
| (T or F) 20) A relationship's maximum cardinality indicates the maximum number of entities that can participate in the relationship. | FALSE Diff: 3 Page Ref: 149 |
| (T or F) 21) In an E-R model, the three types of maximum cardinality are 1:1, 1:N and N:M. | TRUE Diff: 1 Page Ref: 149-150 Fig 5-5 |
| (T or F) 22) In a 1:N relationship, the term parent refers to the N side of the relationship. | FALSE Diff: 2 Page Ref: 149 |
| (T or F) 23) A relationship's minimum cardinality indicates whether or not an entity must participate in the relationship. | TRUE Diff: 1 Page Ref: 149, 150 |
| (T or F) 24) In an E-R model, the three types of minimum cardinality are mandatory, optional and indeterminate. | FALSE Diff: 1 Page Ref: 150-15 Fig 5-6 |
| (T or F) 25) An ID-dependent entity is an entity whose identifier includes the identifier of another entity. | TRUE Diff: 2 Page Ref: 153 Fig 5-12 |
| (T or F) 26) ID-dependent entities are associated by a nonidentifying relationship. | FALSE Diff: 2 Page Ref: 154 |
| (T or F) 27) A weak entity is an entity that cannot exist in the database without (and is logically dependent upon) another type of entity also existing in the database. | TRUE Diff: 3 Page Ref: 155-156 Fig 5-12 |
| (T or F) 28) ID-dependent entities are a common type of weak entity. | TRUE Diff: 2 Page Ref: 154 Fig 5-12 |
| (T or F) 29) All weak entities must have a minimum cardinality of 1 on the entity on which it depends. | TRUE Diff: 3 Page Ref: 155-156 Fig 5-12 |
| (T or F) 30) Subtype entities contain only attributes unique to the subtypes. | TRUE Diff: 3 Page Ref: 156-157 |
| (T or F) 31) An attribute that determines which subtype is appropriate is called a discriminator. | TRUE Diff: 1 Page Ref: 157 |
| (T or F) 32) An exclusive subtype pattern has one supertype entity that relates to one or more subtype entities. | FALSE Diff: 2 Page Ref: 157 |
| (T or F) 33) Entities with an IS-A relationship should have the same identifier. | TRUE Diff: 2 Page Ref: 157 |
| (T or F) 34) One example of a database design using an ID-dependent relationship is the association pattern. | TRUE Diff: 2 Page Ref: 162 |
| (T or F) 35) One example of a database design using a strong relationship is the multivalued attribute pattern. | FALSE Diff: 2 Page Ref: 164 |
| (T or F) 36) One example of a database design using an ID-dependent relationship is the archetype/instance pattern. | TRUE Diff: 2 Page Ref: 166 |
| (T or F) 37) Data modelers agree that weak, non-ID-dependent entities exist and are important. | FALSE Diff: 2 Page Ref: 154-156 |
| (T or F) 38) Relationships among instances of a single entity class are called redundant relationships. | FALSE Diff: 2 Page Ref: 172 |
| (T or F) 39) There are three types of recursive relationships: 1:1, 1:N and N:M. | TRUE Diff: 2 Page Ref: 172-174 |
| (T or F) 40) Recursive relationships only exist for one-to-one relationships. | FALSE Diff: 1 Page Ref: 172-174 |
| 41) Which of the following is not a key element of an E-R model? A) Identifiers B) Entities C) Objects D) Attributes E) Relationships | C Diff: 2 Page Ref: 145-149 |
| 42) Entities of a given type are grouped into a(n) ________. A) entity class B) entity relationship C) entity instance D) entity attribute E) None of the above. | A Diff: 1 Page Ref: 145 |
| 43) The occurrence of a particular entity is called a(n) ________. A) entity class B) entity relationship C) entity instance D) entity attribute E) None of the above. | C Diff: 1 Page Ref: 145 |
| 44) The characteristics of a thing are described by its ________. A) identifiers B) entities C) objects D) attributes E) relationships | D Diff: 1 Page Ref: 146 |
| 45) Attributes may be ________. A) composite B) element C) multivalued D) A and C E) B and C | D Diff: 2 Page Ref: 146 and 150-151 |
| 46) An identifier may be ________. A) composite B) a single attribute C) a relationship D) A and B E) A, B and C | D Diff: 1 Page Ref: 146-147 |
| 47) A composite attribute is an attribute that ________. A) is multivalued B) describes a characteristic of the relationship C) consists of a group of attributes D) is calculated at run-time E) is an identifier | C Diff: 1 Page Ref: 147 |
| 48) For a relationship to be considered a binary relationship it must satisfy which of the following conditions? A) It must involve exactly two entity classes. B) It must have a maximum cardinality of 1:1. C) It must have a maximum cardinality of 1:N. D) A and B E) A and C | A Diff: 3 Page Ref: 147-149 |
| 49) Maximum cardinality refers to ________. A) the most instances of one entity class that can be involved in a relationship instance with another entity class B) the minimum number of entity classes involved in a relationship C) whether or not an instance of one entity class is required to be related to an instance of another entity class D) whether or not an entity is a weak entity E) None of the above. | A Diff: 2 Page Ref: 149 |
| 50) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above, and are asked to draw the relationship between them. If a given customer can place only one order and a given order can be placed by at most one customer, which of the following should be indicated in the relationship symbol between the two entities? A) 0:1 B) 1:1 C) 1:N D) N:1 E) N:M | B Diff: 2 Page Ref: 149-150 |
| 51) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above, and are asked to draw the relationship between them. If a given customer can place many orders and a given order can be placed by at most one customer, which of the following should be indicated in the relationship symbol between the two entities? A) 0:1 B) 1:1 C) 1:N D) N:1 E) N:M | D Diff: 3 Page Ref: 149-150 |
| 52) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above, and are asked to draw the relationship between them. If a given customer can place many orders and a given order can be by one or more customers, which of the following should be indicated in the relationship symbol between the two entities? A) 0:1 B) 1:1 C) 1:N D) N:1 E) N:M | E Diff: 2 Page Ref: 149-150 |
| 53) Minimum cardinality refers to ________. A) the most instances of one entity class that can be involved in a relationship with one instance of another entity class B) the minimum number of entity classes involved in a relationship C) whether or not an instance of one entity class is required to be related to an instance of another entity class D) whether or not an entity is a weak entity E) None of the above. | C Diff: 2 Page Ref: 150 |
| 54) In a minimum cardinality, minimums are generally stated as ________. A) 0 B) 1 C) N D) A or B E) A, B or C | D Diff: 2 Page Ref: 150-151 |
| 55) A hash mark across the relationship line near an entity indicates ________. A) a maximum cardinality of "zero" B) a maximum cardinality of "one" C) a minimum cardinality of "optional" D) a minimum cardinality of "required" E) None of the above. | D Diff: 2 Page Ref: 150-151 |
| 56) A circle across the relationship line near an entity indicates ________. A) a maximum cardinality of "zero" B) a maximum cardinality of "one" C) a minimum cardinality of "optional" D) a minimum cardinality of "required" E) None of the above. | C Diff: 2 Page Ref: 150-151 |
| 57) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above. What does the symbol next to the ORDER entity indicate? A) A maximum cardinality of "zero" B) A maximum cardinality of "one" C) A minimum cardinality of "optional" D) A minimum cardinality of "required" E) None of the above. | C Diff: 2 Page Ref: 150-151 |
| 58) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above. What does the symbol next to the CUSTOMER entity indicate? A) A maximum cardinality of "zero" B) A maximum cardinality of "one" C) A minimum cardinality of "optional" D) A minimum cardinality of "required" E) None of the above. | D Diff: 2 Page Ref: 150-151 |
| 59) An entity whose identifier includes the identifier of another entity is a(n) ________. A) strong entity B) weak entity C) ID-dependent entity D) A and C E) B and C | E Diff: 2 Page Ref: 153-154 |
| 60) An entity whose existence depends on the presence of another entity, but whose identifier does not include the identifier of the other entity is a(n) ________. A) strong entity B) weak entity C) ID-dependent entity D) A and C E) B and C | B Diff: 2 Page Ref: 154-156 |
| 61) An entity that holds specialized attributes that distinguish it from one or more other similar entities is a(n) ________. A) supertype B) subtype C) discriminator D) A and C E) B and C | B Diff: 1 Page Ref: 156-157 |
| 62) Which of the following is not true about subtype entities? A) Subtypes may be exclusive. B) The supertype and subtypes will have the same identifier. C) Subtypes are used to avoid a situation in which some attributes are required to be null. D) Subtypes have attributes that are required by the supertype. E) Subtypes can produce a closer-fitting data model. | E Diff: 3 Page Ref: 156-157 |
| 63) An attribute that determines which subtype should be used is a(n) ________. A) supertype B) subtype C) discriminator D) A and C E) B and C | C Diff: 1 Page Ref: 156-157 |
| 64) Discriminators can be ________. A) exclusive only B) inclusive only C) decisive only D) A or B E) B or C | D Diff: 1 Page Ref: 156-157 |
| 65) Supertype/subtype entities are said to have a(n) ________ relationship. A) HAS-A B) IS-A C) recursive D) redundant E) multivalue | B Diff: 2 Page Ref: 157 |
| 66) To represent an association pattern in an E-R model, ________. A) create a new ID-dependent entity with a 1:1 relationship to one other entity B) create a new weak, but not ID-dependent entity with a 1:1 relationship to one other entity C) create a new strong entity with a 1:1 relationship to one other entity D) create a new ID-dependent entity with a 1:N relationship to one of two parent entities E) create a new weak, but not ID-dependent entity with a 1:N relationship to one of two parent entities | D Diff: 3 Page Ref: 162-164 |
| 67) To represent a multivalued attribute in an E-R model, ________. A) create a new ID-dependent entity with a 1:N relationship B) create a new weak, but not ID-dependent entity with a 1:N relationship C) create a new strong entity with a 1:1 relationship D) create a new ID-dependent entity with a 1:1 relationship E) create a new weak, but not ID-dependent entity with a 1:1 relationship | A Diff: 3 Page Ref: 164-165 |
| 68) To represent an archetype/instance pattern in an E-R model, ________. A) create a new ID-dependent entity with a 1:N relationship B) create a new weak, but not ID-dependent entity with a 1:N relationship C) create a new strong entity with a 1:1 relationship D) create a new ID-dependent entity with a 1:1 relationship E) create a new weak, but not ID-dependent entity with a 1:1 relationship | A Diff: 3 Page Ref: 166-168 |
| 69) When an entity has a relationship to itself, we have a(n) ________. A) supertype/subtype relationship B) archetype/instance relationship C) recursive relationship D) A or C E) B or C | C Diff: 1 Page Ref: 172 |
| 70) Recursive relationships can have which of the following maximum cardinalities? A) 1:1 B) 1:N C) N:M D) A or B E) A, B or C | E Diff: 1 Page Ref: 172-174 |
| 71) A(n) ________ is something that the users want to track in their environment. | entity Diff: 1 Page Ref: 145 |
| 72) The method of constructing data models used in the text is the ________ model. | extended entity-relationship (E-R) Diff: 1 Page Ref: 145 |
| 73) Entities of a given type are grouped into ________. | entity classes Diff: 1 Page Ref: 145 |
| 74) A(n) ________ is the occurrence of a particular entity. | entity instance Diff: 1 Page Ref: 145 |
| 75) A(n) ________ describes a characteristic of an entity. | attribute Diff: 1 Page Ref: 146 |
| 76) A(n) ________ of an entity instance is one or more attributes that name or identify entity instances. | identifier Diff: 1 Page Ref: 146-147 |
| 77) A(n) ________ is an identifier consisting of two or more attributes. | composite identifier Diff: 2 Page Ref: 147 |
| 78) A(n) ________ serves the same role for an entity that a key does for a table. | identifier Diff: 3 Page Ref: 147 |
| 79) Entities can be associated with one another in ________. | relationships Diff: 1 Page Ref: 147 |
| 80) E-R modeling recognizes both relationship ________ and relationship ________. | classes; instances Diff: 2 Page Ref: 147 |
| 81) A relationship class may involve ________ entity classes. | two or more Diff: 3 Page Ref: 148 |
| 82) The ________ of a relationship is the number of entity classes in the relationship. | degree Diff: 2 Page Ref: 148 |
| 83) A ________ is a relationship between two entities. | binary relationship Diff: 2 Page Ref: 148 |
| 84) Relationships of degree two are referred to as ________ relationships. | binary Diff: 2 Page Ref: 148 |
| 85) When transforming a data model into a relational design, relationships of all degrees are treated as combinations of ________. | binary relationships Diff: 3 Page Ref: 148 |
| 86) The principle difference between an entity and a table is that you can express the relationship between entities without using ________. | foreign keys Diff: 3 Page Ref: 148 |
| 87) Relationships are classified by their ________. | cardinality Diff: 1 Page Ref: 149 |
| 88) A relationship's ________ indicates the maximum number of entity instances that can participate in the relationship. | maximum cardinality Diff: 2 Page Ref: 149 |
| 89) The notation 1:N shows the relationship's ________. | maximum cardinality Diff: 2 Page Ref: 149 |
| 90) In a 1:N relationship, ________ is on the one side of the relationship, and the ________ is on the many side of the relationship. | parent entity; child entity Diff: 2 Page Ref: 149 |
| 91) A relationship's ________ indicates the number of entity instances that must participate in the relationship. | minimum cardinality Diff: 2 Page Ref: 149, 150 |
| 92) An entity whose identifier includes the identifier of another entity is called a(n) ________ entity. | ID-dependent Diff: 2 Page Ref: 153-154 |
| 93) An entity that represents something that can exist on its own is called a(n) ________ entity. | strong Diff: 1 Page Ref: 153 |
| 94) E-R models use a(n) ________ to connect entities that are ID-dependent. | identifying relationship Diff: 2 Page Ref: 154 |
| 95) Entities containing optional sets of attributes are often represented using ________. | subtypes Diff: 2 Page Ref: 156-157 |
| 96) The ________ entity contains the attributes that are common to all subtypes. | supertype Diff: 1 Page Ref: 156-157 |
| 97) An attribute that determines which subtype is appropriate is called a ________. | discriminator Diff: 2 Page Ref: 157 |
| 98) Subtypes can be ________ or ________. | exclusive; inclusive Diff: 2 Page Ref: 157 |
| 99) Relationships between supertypes and subtypes are called ________ relationships. | IS-A Diff: 2 Page Ref: 157 |
| 100) Relationships among an entity instance of a single entity class are called ________ relationships. | recursive Diff: 2 Page Ref: 172 |
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