Database MCQ Number 00880

Database MCQ Set 1

1. In SQL, which command is used to issue multiple CREATE TABLE, CREATE VIEW and GRANT statements in a single transaction?
a) CREATE PACKAGE
b) CREATE SCHEMA
c) CREATE CLUSTER
d) All of the mentioned

2. In SQL, the CREATE TABLESPACE is used
a) To create a place in the database for storage of scheme objects, rollback segments, and naming the data files to comprise the tablespace
b) To create a database trigger
c) To add/rename data files, to change storage
d) All of the mentioned

3. Which character function can be used to return a specified portion of a character string?
a) INSTR
b) SUBSTRING
c) SUBSTR
d) POS

4. Which of the following is TRUE for the System Variable $date$?
a) Can be assigned to a global variable
b) Can be assigned to any field only during design time
c) Can be assigned to any variable or field during run time
d) Can be assigned to a local variable

5. What are the different events in Triggers?
a) Define, Create
b) Drop, Comment
c) Insert, Update, Delete
d) Select, Commit

6. Which is the subset of SQL commands used to manipulate Oracle Database Structures, including tables?
a) Data Definition Language
b) Data Manipulation Language
c) Data Described Language
d) Data Retrieval Language

7. The SQL statement SELECT SUBSTR(‘123456789’, INSTR(‘abcabcabc’,’b’), 4) FROM EMP; prints
a) 6789
b) 2345
c) 1234
d) 456789

8. Which of the following SQL command can be used to modify existing data in a database table?
a) MODIFY
b) UPDATE
c) CHANGE
d) NEW

9. When SQL statements are embedded inside 3GL, we call such a program as
a) Nested query
b) Nested programming
c) Distinct query
d) Embedded SQL

10. ___ provides option for entering SQL queries as execution time, rather than at the development stage.
a) PL/SQL
b) SQL*Plus
c) SQL
d) Dynamic SQL

Database MCQ Set 2

1. Snapshot isolation is a particular type of ________ scheme.
a) Concurrency-control
b) Concurrency-allowance
c) Redirection
d) Repetition-allowance

2. Snapshot isolation is used to give
a) Transaction a snapshot of the database
b) Database a snapshot of the transaction
c) Database a snapshot of committed values in the transaction
d) Transaction a snapshot of the database and Database a snapshot of committed values in the transaction

3. Lost update problem is
a) Second update overwrites the first
b) First update overwrites the second
c) The updates are lost due to conflicting problem
d) None of the mentioned

4. Under first updater wins the system uses a ____ mechanism that applies only to updates.
a) Close
b) Read
c) Locking
d) Beat

5. When a transaction Ti attempts to update a data item, it requests a ___ on that data item.
a) Read lock
b) Update lock
c) Write lock
d) Chain lock

6. Each of a pair of transactions has read data that is written by the other, but there is no data written by both transactions, is referred to as
a) Read skew
b) Update skew
c) Write lock
d) None of the mentioned

7. An application developer can guard against certain snapshot anomalies by appending a ______ clause to the SQL select query.
a) For update
b) For read
c) For write
d) None of the mentioned

8. Evaluate the CREATE TABLE statement:

CREATE TABLE products
(product_id NUMBER(6) CONSTRAINT prod_id_pk PRIMARY KEY, product_name VARCHAR2(15));

Which statement is true regarding the PROD_ID_PK constraint?
a) It would be created only if a unique index is manually created first
b) It would be created and would use an automatically created unique index
c) It would be created and would use an automatically created no unique index
d) It would be created and remains in a disabled state because no index is specified in the command

9. Evaluate the following CREATE SEQUENCE statement:

CREATE SEQUENCE seq1
START WITH 100
INCREMENT BY 10
MAXVALUE 200
CYCLE
NOCACHE;

The sequence SEQ1 has generated numbers up to the maximum limit of 200. You issue the following SQL statement:
SELECT seq1.nextval FROM dual;
What is displayed by the SELECT statement?
a) 1
b) 10
c) 100
d) an error

10. In which scenario would you use the ROLLUP operator for expression or columns within a GROUP BY clause?
a) To find the groups forming the subtotal in a row
b) To create group-wise grand totals for the groups specified within a GROUP BY clause
c) To create a grouping for expressions or columns specified within a GROUP BY clause in one direction, from
right to left for calculating the subtotals
d) To create a grouping for expressions or columns specified within a GROUP BY clause in all possible
directions, which is cross-tabular report for calculating the subtotals

Database MCQ Set 3

1. Two main measures for the efficiency of an algorithm are
a) Processor and memory
b) Complexity and capacity
c) Time and space
d) Data and space

2. The time factor when determining the efficiency of algorithm is measured by
a) Counting microseconds
b) Counting the number of key operations
c) Counting the number of statements
d) Counting the kilobytes of algorithm

3. The space factor when determining the efficiency of algorithm is measured by
a) Counting the maximum memory needed by the algorithm
b) Counting the minimum memory needed by the algorithm
c) Counting the average memory needed by the algorithm
d) Counting the maximum disk space needed by the algorithm

4. Which of the following case does not exist in complexity theory
a) Best case
b) Worst case
c) Average case
d) Null case

5. The Worst case occur in linear search algorithm when
a) Item is somewhere in the middle of the array
b) Item is not in the array at all
c) Item is the last element in the array
d) Item is the last element in the array or is not there at all

6. The Average case occur in linear search algorithm
a) When Item is somewhere in the middle of the array
b) When Item is not in the array at all
c) When Item is the last element in the array
d) When Item is the last element in the array or is not there at all

7. The complexity of the average case of an algorithm is
a) Much more complicated to analyze than that of worst case
b) Much more simpler to analyze than that of worst case
c) Sometimes more complicated and some other times simpler than that of worst case
d) None of the mentioned

8. The complexity of linear search algorithm is
a) O(n)
b) O(log n)
c) O(n2)
d) O(n log n)

9. The complexity of Binary search algorithm is
a) O(n)
b) O(log )
c) O(n2)
d) O(n log n)

10. The complexity of Bubble sort algorithm is
a) O(n)
b) O(log n)
c) O(n2)
d) O(n log n)

Database MCQ Set 4

1. Which one of the following is used to define the structure of the relation ,deleting relations and relating schemas ?
a) DML(Data Manipulation Langauge)
b) DDL(Data Definition Langauge)
c) Query
d) Relational Schema

2. Which one of the following provides the ability to query information from the database and to insert tuples into, delete tuples from, and modify tuples in the database ?
a) DML(Data Manipulation Langauge)
b) DDL(Data Definition Langauge)
c) Query
d) Relational Schema

3. Create table employee (name varchar ,id integer)
What type of statement is this ?
a) DML
b) DDL
c) View
d) Integrity constraint

4. Select * from employee
What type of statement is this?
a) DML
b) DDL
c) View
d) Integrity constraint

5. The basic data type char(n) is a _____ length character string and varchar(n) is _____ length character.
a) Fixed, equal
b) Equal, variable
c) Fixed, variable
d) Variable, equal

6. An attribute A of datatype varchar(20) has the value “Avi” . The attribute B of datatype char(20) has value ”Reed” .Here attribute A has ____ spaces and attribute B has ____ spaces.
a) 3, 20
b) 20, 4
c) 20 , 20
d) 3, 4

7. To remove a relation from an SQL database, we use the ______ command.
a) Delete
b) Purge
c) Remove
d) Drop table

8. Delete from r; r – relation
This command performs which of the following action ?
a) Remove relation
b) Clear relation entries
c) Delete fields
d) Delete rows

9. Insert into instructor values (10211, ’Smith’, ’Biology’, 66000);
What type of statement is this ?
a) Query
b) DML
c) Relational
d) DDL

10. Updates that violate ____ are disallowed.
a) Integrity constraints
b) Transaction control
c) Authorization
d) DDL constraints

Database MCQ Set 5

1.

Which of these query will display the the table given above ?
a) Select employee from name
b) Select name
c) Select name from employee
d) Select employee

2. Select ________ dept_name
from instructor;
Here which of the following displays the unique values of the column ?
a) All
b) From
c) Distinct
d) Name

3. The ______ clause allows us to select only those rows in the result relation of the ____ clause that satisfy a specified predicate.
a) Where, from
b) From, select
c) Select, from
d) From, where

4. Select ID, name, dept name, salary * 1.1
where instructor;
The query given below will not give an error. Which one of the following has to be replaced to get the desired output?
a) Salary*1.1
b) ID
c) Where
d) Instructor

5. The ________ clause is used to list the attributes desired in the result of a query.
a) Where
b) Select
c) From
d) Distinct

6. Select name, course_id
from instructor, teaches
where instructor_ID= teaches_ID;
This Query can be replaced by which one of the following ?
a) Select name,course_id from teaches,instructor where instructor_id=course_id;
b) Select name, course_id from instructor natural join teaches;
c) Select name ,course_id from instructor;
d) Select course_id from instructor join teaches;

7. Select * from employee where salary>10000 and dept_id=101;
Which of the following fields are displayed as output?
a) Salary, dept_id
b) Employee
c) Salary
d) All the field of employee relation

8.

This is Employee table.
Select * from employee where employee_id>1009;
Which of the following employee_id will be displayed?
a) 1009, 1001, 1018
b) 1009, 1018
c) 1001
d) 1018

9. Which of the following statements contains an error?
A) Select * from emp where empid = 10003;
B) Select empid from emp where empid = 10006;
C) Select empid from emp;
D) Select empid where empid = 1009 and lastname = ‘GELLER’;

10. Insert into employee _____ (1002,Joey,2000);
In the given query which of the keyword has to be inserted ?
a) Table
b) Values
c) Relation
d) Field

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