Database Processing Chapter 5-6

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) It must involve exactly two entity classes

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) create a new ID-dependent entity with a 1:N relationship

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) create a new ID-dependent entity with a 1:N relationship

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) entity class

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) the most instances of one entity class that can be involved in a relationship instance with another entity class

------------requires that one entity must be combined with another entity in the ternary (or higher-order) relationship. A- MUST constraint B- MUST NOT constraint C- MUST COVER constraint

A- MUST constraint

Each attribute of an entity becomes a ________ of a table. A) column B) primary key C) foreign key D) alternate key E) B or D

Answer: A Diff: 1 Page Ref: 193 Fig 6-1

When transforming an E-R data model into a relational database design, the key of the parent entity should be placed as part of the primary key into the child entity ________. A) when the child entity is ID-dependent B) when the child entity is non-ID-dependent C) when the child entity has a 1:1 relationship with the parent entity D) when the child entity has a 1:N relationship with the parent entity E) when the child entity has a recursive relationship with the parent entity

Answer: A Diff: 2 Page Ref: 201, 207

To which of the following actions are referential integrity constraints not applied? A) create B) insert C) modify D) delete E) referential integrity constraints are applied to all of the listed actions

Answer: A Diff: 2 Page Ref: 214-216 Fig 6-28

In a relational database design, all relationships are expressed by ________. A) creating a primary key B) creating a foreign key C) creating a supertype D) creating a subtype E) creating a line between entities

Answer: B

c

Answer: B Diff: 1 Page Ref: 198-199

To represent a one-to-many relationship in a relational database design ________. A) the key of the child is placed as a foreign key into the parent B) the key of the parent is placed as a foreign key into the child C) an intersection table must be created D) the key of the table on the "many" side is placed in the table on the "one" side E) the keys of both tables are joined into a composite key

Answer: B Diff: 2 Page Ref: 199

Which of the following is not true about representing subtypes in a relational database design? A) One table is created for the supertype and one for each subtype. B) All of the attributes of the supertype are added to the subtype relations. C) The key of the supertype is made the key of the subtypes. D) A subtype and its supertype are representations of the same underlying table. E) An instance of the supertype may be related to one instance each of several subtypes.

Answer: B Diff: 2 Page Ref: 208

Which of the following is not true about surrogate keys? A) They are identifiers that are supplied by the system, not the users. B) They have no meaning to the users. C) They are nonunique within a table. D) They can be problematic when combining databases. E) The DBMS will not allow their values to be changed

Answer: C

A surrogate key should be considered when ________. A) a relationship is M:N B) a composite key is required C) the key contains a lengthy text field D) the key contains a number E) an index needs to be created

Answer: C Diff: 3 Page Ref: 194

A referential integrity constraint policy that insures that foreign key values in a table are correctly maintained when there is a change to the primary key value in the parent table is called ________. A) incremental updates B) incremental deletes C) controlled key adjustments D) cascading updates E) cascading deletes

Answer: D Diff: 1 Page Ref: 216

Many-to-many relationships are represented by ________. A) two tables with an M:N relationship B) two tables with a 1:N relationship C) an intersection table which has M:N relationships with the two tables D) an intersection table which has 1:N relationships with the two tables E) two intersection tables which each have 1:N relationships with the two tables

Answer: D Diff: 2 Page Ref: 199-201

A referential integrity constraint policy that guarantees that a row in a parent table always has a required entry in a child table ________. A) is known as a minimum cardinality enforcement action B) needs to be documented by the database development team C) is enforced in most DBMS products D) A and B E) A, B and C

Answer: D Diff: 3 Page Ref: 216-217 Fig 6-28

In relational database design, ID-dependent entities are used to ________. A) represent N:M relationships B) handle associative relationships C) handle multivalued attributes D) handle archetype/instance relationships E) All of the above.

Answer: E Diff: 2 Page Ref: 201 Fig 6-11

Which of the following is not true of recursive relationships? A) When the recursive relationship is M:N, an intersection table is created. B) The rows of a single table can play two different roles. C) The techniques for representing the tables are the same as for non-recursive relationships except the rows are in the same table. D) Recursive relationships can be 1:1, 1:N, or M:N relationships. E) Even when the relationship is 1:N, a new table must be defined to represent the relationship.

Answer: E Diff: 2 Page Ref: 208-210

The binary constraint MUST NOT indicates that ________. A) a specific binary relationship must not be included in a ternary relationship B) a table includes values that must not occur in a binary relationship C) a table includes values that must not occur in a ternary relationship D) a binary relationship includes value combinations that must not occur in a binary relationship E) a binary relationship includes value combinations that must not occur in a ternary relationship

Answer: E Diff: 2 Page Ref: 211-212

When transforming an ID-dependent E-R data model relationship into a relational database design and the parent entity has a surrogate primary key and the child entity has a data identifier, then the primary key of the child table should be ________. A) the parent's surrogate key + the child's data key B) the parent's surrogate key + a surrogate key in the child C) either A or B will work, and neither way is preferable D) either A or B will work, and method A is preferable E) either A or B will work, but method B is preferable

Answer: E Diff: 3 Page Ref: 201, 206

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) 1:1

Supertype/subtype entities are said to have a(n) ________ relationship. A) HAS-A B) IS-A C) recursive D) redundant E) multivalue

B) IS-A

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) subtype

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) weak entity

--------------requires that certain combinations of two entities are not allowed to occur in the ternary (or higher-order) relationship. A- MUST constraint B- MUST NOT constraint C- MUST COVER constraint

B- MUST NOT constraint

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) A minimum cardinality of "optional"

Chapter 5 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) Objects

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) a minimum cardinality of "optional"

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) consists of a group of attributes

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) discriminator

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) entity instance

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) recursive relationship

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) whether or not an instance of one entity class is required to be related to an instance of another entity class

-------------a binary relationship specifies all combinations of two entities that must appear in the ternary (or higher-order) relationship. A- MUST constraint B- MUST NOT constraint C- MUST COVER constraint

C- MUST COVER constraint

The first step in transforming an extended E-R model into a relational database design is to ________.

Create a table for each entity.

An identifier may be ________. A) composite B) a single attribute C) a relationship D) A and B E) A, B and C

D) A and B

Attributes may be ________. A) composite B) element C) multivalued D) A and C E) B and C

D) A and C

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) A minimum cardinality of "required"

Discriminators can be ________. A) exclusive only B) inclusive only C) decisive only D) A or B E) B or C

D) A or B

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) A or B

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) N:1

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) a minimum cardinality of "required"

The characteristics of a thing are described by its ________. A) identifiers B) entities C) objects D) attributes E) relationships

D) attributes

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) create a new ID-dependent entity with a 1:N relationship to one of two parent entities

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) A, B or C

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) B and C

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) N:M

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) Subtypes can produce a closer-fitting data model.

The ideal primary key is ________

Short, Numeric and fixed