Question 1

Explain the representation of a many-to-many strong entity relationship in a relational database design.

Accepted Answer

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Question 2

Which of the following is not true of ternary relationships?
A)Can be treated as a collection of binary relationships
B)Are represented in the same way as binary relationships
C)Must involve at least one M:N relationship
D)Involve three entities of different logical types
E)Often require documentation of special considerations as business rules

Accepted Answer

Ternary relationships do not necessarily have to involve an M:N relationship. They can involve any combination of one-to-one, one-to-many, or many-to-many relationships between the three entities involved.

Question 3

How are one-to-one recursive relationships addressed using the relational model?

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Question 4

When transforming an ID-dependent E-R data model relationship into a relational database design,the referential integrity constraints should allow ________.
A)parent updates to cascade
B)child updates to cascade
C)child deletes to cascade
D)A and B
E)A,B,and C

Accepted Answer

In an ID-dependent E-R data model, the child entity's existence is dependent on the parent entity. Therefore, when a parent entity is updated, the changes should cascade to the child to maintain referential integrity.

Question 5

A referential integrity constraint policy that insures that all rows containing a particular foreign key value in a table are eliminated from the table when the row containing the corresponding primary key value in a parent table is eliminated from the database is called ________.
A)incremental updates
B)incremental deletes
C)controlled key adjustments
D)cascading updates
E)cascading deletes

Accepted Answer

Cascading deletes is the referential integrity constraint policy that ensures that all rows containing a particular foreign key value in a table are eliminated from the table when the row containing the corresponding primary key value in a parent table is eliminated from the database. Therefore, option E is the best choice. The other options are not relevant to the given scenario.

Question 6

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.

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Question 7

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.

Accepted Answer

The answer of Which of the following is not true...

Question 8

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.

Accepted Answer

Recursive relationships do not require a new table to be defined when the relationship is 1:N. Instead, the relationship can be represented with a foreign key within the same table. Therefore, choice E is not true.

Question 9

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

Accepted Answer

The binary constraint "MUST NOT" indicates that certain value combinations in a binary relationship should not occur in a ternary relationship.

Question 10

When transforming an ID-dependent E-R data model relationship into a relational database design and the child entity is designed to use a surrogate key,then ________.
A)the parent entity must also use a surrogate key
B)the relationship remains an ID-dependent relationship
C)the relationship changes to a non-ID-dependent relationship
D)A and B
E)A and C

Accepted Answer

When a child entity uses a surrogate key, the relationship changes to a non-ID-dependent relationship because the surrogate key replaces the need for the child entity's primary key to include the parent's primary key.

Question 11

What are MUST NOT and MUST COVER constraints?

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The answer of What are MUST NOT and MUST COVER...

Question 12

In a supertype-subtype structure,discriminator attributes ________.
A)are easily represented in a relational design
B)cannot be represented in a relational design
C)require application logic to determine which subtypes correspond to a specific supertype instance
D)A and C
E)B and C

Accepted Answer

The answer of In a supertype-subtype structure,discriminator attributes ________.
A)are easily...

Question 13

The binary constraint MUST COVER indicates that ________.
A)a specific binary relationship must be included in a ternary relationship
B)a table includes values that must occur in a binary relationship
C)a table includes values that must occur in a ternary relationship
D)a binary relationship includes value combinations that must occur in a binary relationship
E)a binary relationship includes a set of value combinations that must all occur in a ternary relationship

Accepted Answer

The MUST COVER constraint in a binary relationship specifies that all combinations of values in the binary relationship must be present in the ternary relationship.

Question 14

Explain the representation of a one-to-many strong entity relationship in a relational database design.

Accepted Answer

The answer of Explain the representation of a one-to-many strong...

Question 15

Briefly describe the process of converting an extended E-R model into a relational database design.

Accepted Answer

The answer of Briefly describe the process of converting an...

Question 16

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

Accepted Answer

The answer of A referential integrity constraint policy that guarantees...

Question 17

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

Accepted Answer

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 cascading updates. This means that when a primary key value is updated in the parent table, the corresponding foreign key values in the child tables are also updated with the new primary key value.

Question 18

What is an association relationship and how does it differ from an N:M relationship?

Accepted Answer

The answer of What is an association relationship and how...

Question 19

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,but method A is preferable
E)either A or B will work,but method B is preferable

Accepted Answer

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Question 20

Explain the pragmatic reason for using surrogate keys.

Accepted Answer

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Quiz 6: Transforming Data Models Into Database Designs

Explain the representation of a many-to-many strong entity relationship in a relational database design.

Which of the following is not true of ternary relationships?

How are one-to-one recursive relationships addressed using the relational model?

When transforming an ID-dependent E-R data model relationship into a relational database design,the referential integrity constraints should allow ________.

A referential integrity constraint policy that insures that all rows containing a particular foreign key value in a table are eliminated from the table when the row containing the corresponding primary key value in a parent table is eliminated from the database is called ________.

To which of the following actions are referential integrity constraints not applied?

Which of the following is not true about representing subtypes in a relational database design?

Which of the following is not true of recursive relationships?

The binary constraint MUST NOT indicates that ________.

When transforming an ID-dependent E-R data model relationship into a relational database design and the child entity is designed to use a surrogate key,then ________.

What are MUST NOT and MUST COVER constraints?

In a supertype-subtype structure,discriminator attributes ________.

The binary constraint MUST COVER indicates that ________.

Explain the representation of a one-to-many strong entity relationship in a relational database design.

Briefly describe the process of converting an extended E-R model into a relational database design.

A referential integrity constraint policy that guarantees that a row in a parent table always has a required entry in a child table ________.

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 ________.

What is an association relationship and how does it differ from an N:M relationship?

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 ________.

Explain the pragmatic reason for using surrogate keys.