DataBase Management System Questions - 3

                                                        Questions

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Most data models have certain conventions for displaying schemas as diagrams. A displayed schema is called a

Select one:

a. Schema Diagram

b. Data Diagram

c. Program diagram

d. Object Diagram

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The correct answer is: Schema Diagram

Question 2

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A3024. The set of attributes that can uniquely identify weak entities are called as

Select one:

a. Partial key

b. Foreign key

c. Primary key

d. Candidate key

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The correct answer is: Primary key

Question 3

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Copying files to secondary or specific devices is known as______

Select one:

a. Deadlock

b. Retrieve

c. Backup

d. Recovery

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The correct answer is: Backup

Question 4

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Schema normalization is not for

Select one:

a. reducing the number of tables in the schema.

b. eliminating anomalies that could otherwise occur with inserts.

c. eliminating uncontrolled redundancy of data.

d. ensuring that functional dependencies are enforced.

e. eliminating anomalies that could otherwise occur with deletes.

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The correct answer is: reducing the number of tables in the schema.

Question 5

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In an E-R, Y is the dominant entity and X is a subordinate entity. Then which of the following is incorrect :

Select one:

a. existence is dependent on Y.

b. Operationally, if X is deleted, & remains the same.

c. Operationally, if Y is deleted, so is X

d. Operationally, if X is deleted, so is Y.

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The correct answer is: Operationally, if X is deleted, so is Y.

Question 6

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Updating a data base means

Select one:

a. modifying or adding record occurrences

b. revising the file structure

c. All of these

d. reorganizing the database

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The correct answer is: revising the file structure

Question 7

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If an attribute of a composite key is dependent on an attribute of the other composite key, a normalization called _____ is needed.

Select one:

a. DKNF

b. Fourth

c. BCNF

d. Third

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The correct answer is: BCNF

Question 8

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The data dictionary/repository contains:

Select one:

a. definitions of all the tables, columns, data domains and assumptions used in the database

b. help files for working with databases

c. all of the given choices.

d. all the data contained in the database

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The correct answer is: definitions of all the tables, columns, data domains and assumptions used in the database

Question 9

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All candidate keys other than primary keys are called

Select one:

a. Alternate keys.

b. Eligible keys

c. Secondary keys

d. None of the given choices

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The correct answer is: Alternate keys.

Question 10

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_____ symbol is used to denote the RENAME operation.

Select one:

a. ∞

b. ρ

c. σ

d. π

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The correct answer is: ρ

Question 11

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A relationship is

Select one:

a. related data

b. an item in an application

c. a meaningful dependency between entities

d. a collection of related entities

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The correct answer is: a meaningful dependency between entities

Question 12

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Which object contains the Position property of the current record in a dataset?

Select one:

a. DataBinding

b. Bindingcontext

c. Datacontext

d. DataBound

e. BindingData

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The correct answer is: Bindingcontext

Question 13

Question text

In the architecture of a database system external level is the

Select one:

a. conceptual level

b. logical level.

c. physical level.

d. view level.

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The correct answer is: view level.

Question 14

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A database schema is

Select one:

a. a description of the database using a specific data model

b. the content of the database

c. the state of a database

d. the collection of related data

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The correct answer is: a description of the database using a specific data model

Question 15

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Which SQL statement selects all rows from a table called Products and orders the result set by ProductID column?

Select one:

a. SELECT * FROM Products ORDER BY ProductID

b. SELECT * FROM Products ORDERED BY ProductID

c. SELECT ProductID FROM Products

d. SELECT * FROM Products WHERE ProductID > 200

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The correct answer is: SELECT * FROM Products ORDER BY ProductID

Question 16

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B4042 Consider the relation Emps(empID, ssNo, name, mgrID). Suppose we wish to find the ID’s of the employees who do not manage any employee named “Sally.” Here are two possible queries: I. SELECT mgrID FROM Emps WHERE NOT EXISTS(SELECT * FROM Emps WHERE NAME = ‘Sally’); II. SELECT mgrID FROM Emps WHERE NOT (empID = ANY(SELECT EmpID FROM Emps WHERE name = ‘Sally’)); Which, if any, of the two queries above will correctly (in SQL2) get the desired set of employee ID’s?

Select one:

a. I only

b. Neither I nor II

c. II only

d. Both I and II

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The correct answer is: Neither I nor II

Question 17

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The relation employee(ID,name,street,Credit,street,city,salary) is decomposed into employee1 (ID, name); employee2 (name, street, city, salary); This type of decomposition is called

Select one:

a. Both a and b

b. None of the mentioned

c. Lossless-join decomposition

d. Lossless decomposition

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The correct answer is: None of the mentioned

Question 18

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How to select all data from studentinfo table starting the name from letter 'r'?

Select one:

a. SELECT * FROM studentinfo WHERE sname LIKE '%r';

b. SELECT * FROM studentinfo WHERE sname LIKE '_r%';

c. SELECT * FROM studentinfo WHERE sname LIKE '%r%';

d. SELECT * FROM studentinfo WHERE sname LIKE 'r%';

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The correct answer is: SELECT * FROM studentinfo WHERE sname LIKE 'r%';

Question 19

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Why is it a good idea to use special associations when drawing class diagrams?

Select one:

a. It is necessary. It is impossible to draw some diagrams without using these special structures

b. Specialized tools are available to create these special associations

c. They hide the detail concerning the database structure, making them easier to understand

d. They convey more information about the underlying structure of the database, making them easier to understand

Question 20

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Which of the following is top down approach

Select one:

a. Categorization

b. Specialization

c. Generalization

d. None of the given choices

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The correct answer is: Specialization

Question 21

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. Several contiguous blocks are called as ---------------

Select one:

a. Group

b. None of the given choices

c. Buffer

d. Cluster

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The correct answer is: Cluster

Question 22

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Which is duplication of computer operations and routine backups to combat any unforeseen problems:

Select one:

a. Recovery

b. Deadlock

c. Concurrency

d. Backup

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The correct answer is: Recovery

Question 23

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A foreign key:

Select one:

a. is found in tables that don’t have a primary key.

b. is related to the primary key of a different table.

c. is a unique record in a table.

d. has nothing to do with the primary key.

e. has different values than the primary key.

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The correct answer is: is related to the primary key of a different table.

Question 24

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In case of entity integrity, the primary key may be

Select one:

a. any value.

b. Null

c. not Null

d. both Null & not Null.

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The correct answer is: not Null

Question 25

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Suppose relation R(A,B,C,D,E) has the following functional dependencies: A -> B, B -> C, BC -> A, A -> D, E -> A, D -> E Which of the following is not a key?

Select one:

a. B,C

b. D

c. E

d. A

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The correct answer is: B,C