Ensurepass

Question 91

A theta-join can be viewed as:

 

A. the intersection of two relations.

B. a Cartesian product of two relations.

C. a restricted Cartesian product of two relations.

D. the Cartesian product of two union-compatible relations.

 

Answer: C

 

 

Question 92 In

which situation would the DBMS use a serial schedule to execute the transactions?

 

A. Concurrent transactions read data from the same data structure.

B. Concurrent transactions write data to different data structures.

C. Concurrent transactions read or write the same data structure.

D. Concurrent transactions read or write from different data structures.

 

Answer: C

 

 

Question 93

To create a view, what are the minimal privileges that a user must have for the relations used to make the view?

 

A. GRANT

B. REVOKE

C. SELECT

D. CREATE VIEW

 

Answer: C

 

 

Question 94

Which of the following best describes the ON DELETE CASCADE referential integrity constraint?

 

A. If a parent key is deleted, any child keys referenced by the parent key are automatically deleted.

B. If any child key references a parent key, the record containing the parent key cannot be deleted.

C. If a parent key is deleted, all child keys are automatically set to a specified value.

D. If a parent key is deleted, no test is made for referential integrity.

 

Answer: A

 

 

Question 95

Your enterprise must decide whether to use a database management system. Which of the following best describes the overall functionality of a DBMS?

 

A. A DBMS provides the ability to control data access using Data Manipulation Language.

B. A DBMS provides the ability to maintain databases while providing increased security for the database.

C. A DBMS allows users to access the database while allowing only the database administrator to define user views.

D. A DBMS provides the ability to define, create and maintain databases while providing controlled access to databases.

 

Answer: D

 

 

Question 96

Which of the following definitions applies to all types of databases?

 

A. Data that is stored as tables

B. Software that manipulates data

C. Data that is stored in a structured manner

D. Data records that are stored sequentially in a file

 

Answer: C

 

 

Question 97

Consider the entity-relation (ER) diagram shown in the exhibit. When the logical database design phase is completed, which of the following is a valid DBDL description of the base relations for the ER diagram?

clip_image002

A. STUDENT(

Student_Number: integer NOT NULL

Name: variable length character string length 20 NOT NULL) Primary Key Student_Number

CLASS(

Class_Num: integer NOT NULL Class_Name: integer NOT NULL) Primary Key Class_Num

B. STUDENT(

Student_Number: integer NOT NULL

Name: variable length character string length 20 NOT NULL) Primary Key Student_Number

CLASS(

Class_Num: integer NOT NULL Class_Name: integer NOT NULL) Primary Key Class_Num

Foreign Key Class_Num References STUDENT

C. STUDENT(

Student_Number: integer NOT NULL

Name: variable length character string length 20 NOT NULL) Primary Key Student_Number

STU_CLASS(

Student_Number: integer NOT NULL Class_Num: integer NOT NULL) Primary Key Student_Number CLASS(

Class_Num: integer NOT NULL Class_Name: integer NOT NULL) Primary Key Class_Num

D. STUDENT(

Student_Number: integer NOT NULL

Name: variable length character string length 20 NOT NULL) Primary Key Student_Number

STU_CLASS(

Student_Number: integer NOT NULL Class_Num: integer NOT NULL) Primary Key Student_Number CLASS(

Class_Num: integer NOT NULL Class_Name: integer NOT NULL) Primary Key Class_Num

 

Answer: D

 

 

Question 98

Which pair of relational algebraic operations requires union compatibility?

 

A. Projection and Cartesian product

B. Selection and projection

C. Intersection and difference

D. Cartesian product and intersection

 

Answer: C

 

 

Question 99

Consider the Recreation relation in the exhibit. A data operation that changes one of the tuples for Student_ID 1003 must be performed. It is necessary to change one of the activities from swimming to tennis. The Student_ID and Activity attributes make up the primary key for the Recreation relation. All related information must be altered, as well. Which SQL statement or statements would best accomplish this?

clip_image004

A. UPDATE Recreation

SET Activity, Activity_Fee (‘Tennis’, 100) WHERE Student_ID = 1003;

B. UPDATE TABLE Recreation

SET ACTIVITY = ‘Tennis’, Activity_Fee = 100 WHERE Student_ID = 1003

AND Activity = Swimming;

C. UPDATE Recreation

SET Activity = ‘Tennis’, Activity_Fee = 100 WHERE Student_ID = 1003

AND Activity = ‘Swimming’;

D. DELETE Activity FROM Recreation

WHERE Student_ID = 1003; INSERT INTO Recreation VALUES (1003, ‘Tennis’, 100);

 

Answer: C

 

 

Question 100

Consider the following four database design activities: 1 – Design user views.

2 – Select a DBMS.

3 – Apply normalization. 4 – Determine entities.

Which choice shows the correct ordering of these activities, from first to last, by assigned numbers?

 

A. 1, 2, 3, 4

B. 3, 4, 1, 2

C. 4, 1, 3, 2

D. 4, 2, 3, 1

 

Answer: D

 

 

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