Multiple Choice Questions and Answers
MCQ on Relational Database Management System
1. MCQ:
In the relational model, the row of the table is known to be
A. Relation
B.
Attribute
C. Tuple
D. Entity field
Answer
2. MCQ:
Relational model eases the job of the programmer, compared to earlier data
models such as
A. Network model
B.
Hierarchical model
C.
Semistructured model
D. Both A and B
Answer
3. MCQ:
To refer to a specific instance of a relation in the relational model, the term
used is known as
A. Relation instance
B.
Relation entity
C.
Relation tuple
D. Relation attribute
Answer
4. MCQ:
A property of the entire relation, rather than of the individual tuples, is
known as
A. Attribute
B.
Constant
C.
Variable
D. Key
Answer
Answer
Answer
5. MCQ:
Minimal superkeys are called
A. Unique key
B.
Superset key
C. Candidate key
D. Primary key
Answer
6. MCQ:
A table is a collection of relationships, there is a close correspondence
between the concept of
A. Tables and instances
B.
Tables and Entries
C.
Table and variables
D. Tables and relations
Answer
7. MCQ:
The term that says values appearing in specified attributes of any tuple in the
referencing relation also appear in specified attributes of at least one tuple
in the referenced relation, is called
A. Constant Integrity constraint
B.
Variable Integrity constraint
C. Referential Integrity
constraint
D. Attribute Integrity constraint
Answer
8. MCQ:
A relation, say r1, may include among its attributes the primary key of another
relation, say r2. the r1 is also known as
A. Parent relation
B.
Referenced relation
C. Referencing relation
D. Node relation
9. MCQ:
In the relational model, the column of the table is known to be
A. Entity field
B. Attribute
C.
Tuple
D. Relation
a. Answer
10.
MCQ: The contents of a relation instance may change
with time as the relation
A. Domain
B.
Time
C. Updated
D. Retrieved
Answer
11.
MCQ: The query languages are usually on a level higher
than that of a standard
A. Updation language
B.
Query program language
C.
Procedural language
D. Programming language
Answer
12.
MCQ: Query languages used in practice includes
A. Elements
B.
Fields
C.
Instances
D. Tuples
Answer
13.
MCQ: A set of one or more attributes that
collectively, allow us to identify uniquely a tuple in the relation, is known
as
A. Unique key
B.
Special key
C. Super key
D. Primary key
14.
MCQ: A relation schema consists of a list of
attributes and their corresponding
A. Variables
B.
Instances
C. Domains
D. Tuples
Answer
15.
MCQ: A row in a table represents a relationship among
a
A. Procedures
B. Set of values
C.
Sequence of values
D. Entities
Answer
16.
MCQ: The logical design of the database, is known to
be
A. Database instance
B.
Database entity
C.
Database relation
D. Database Schema
Answer
17.
MCQ: The type of query in which user describes the
desired information without giving a specific procedure for obtaining that
information, is known to be
A. Procedural language
B. Nonprocedural
language
C.
Programming language
D. Query program
18.
MCQ: The address field of a person should not be part
of the primary key, since it is likely to
A. Dependent
B. Changed
C.
Not changed
D. Too long
19.
MCQ: The primary key should be chosen such that its
attribute values are
A. Updated
B.
Dependent
C.
Changed
D. Never changed
20.
MCQ: The user instructs the system to perform a
sequence of operations on the database to compute the desired outcome, is known
as
A. Programming language
B.
Query program
C. Procedural language
D. Nonprocedural language
Answer
21.
MCQ: The relational model is today the primary data
model for commercial
A. Data management applications
B.
Data storage applications
C. Data processing
applications
D. Data program application
Answer
22.
MCQ: The query language is a language in which a user
A. Requests
B.
Response
C.
Stores
D. Represents
Answer
23.
MCQ: A snapshot of the data in the database at a given
instant in time, is known as
A. Database entity
B.
Database relation
C. Database instance
D. Database Schema
Answer
24.
MCQ: We are often interested in superkeys for which no
proper subset is a
A. Superset key
B. Superkey
C.
Primary key
D. Unique key
U
1. Which of the following statements is true
about implicit cursors?
A. Implicit
cursors are used for SQL statements that are not named.
B.
Developers should use implicit cursors with great care.
C. Implicit
cursors are used in cursor for loops to handle data processing.
D. Implicit
cursors are no longer a feature in Oracle.
Ans: A
2. Which of the following is not a feature of
a cursor FOR loop?
A. Record
type declaration.
B. Opening
and parsing of SQL statements.
C. Fetches
records from cursor.
D. Requires
exit condition to be defined.
Ans:B
3. A developer would like to use referential
datatype declaration on a variable. The variable name is EMPLOYEE_LASTNAME, and
the corresponding table and column is EMPLOYEE, and LNAME, respectively. How
would the developer define this variable using referential datatypes?
A. Use
employee.lname%type.
B. Use
employee.lname%rowtype.
C. Look up
datatype for EMPLOYEE column on LASTNAME table and use that.
D. Declare
it to be type LONG.
Ans: A
4. Which three of the following are implicit
cursor attributes?
A. %found
B.
%too_many_rows
C.
%notfound
D.
%rowcount
E. %rowtype
Ans:C
5. If left out, which of the following would
cause an infinite loop to occur in a simple loop?
A. LOOP
B. END LOOP
C. IF-THEN
D. EXIT
Ans:B
6. Which line in the following statement will
produce an error?
A. cursor
action_cursor is
B. select
name, rate, action
C. into
action_record
D. from
action_table;
E. There
are no errors in this statement.
Ans:C
7. The command used to open a CURSOR FOR loop
is
A. open
B. fetch
C. parse
D. None,
cursor for loops handle cursor opening implicitly.
Ans:D
8. What happens when rows are found using a
FETCH statement
A. It
causes the cursor to close
B. It
causes the cursor to open
C. It loads
the current row values into variables
D. It
creates the variables to hold the current row values
Ans: B
9. What is the maximum number of handlers
processed before the PL/SQL block is exited when an exception occurs?
A. Only one
B. All that
apply
C. All
referenced
D. None
Ans: A
10. For which trigger timing can you
reference the NEW and OLD qualifiers?
A.
Statement and Row
B.
Statement only
C. Row only
D. Oracle
Forms trigger
Ans: D
11. Which identifier is valid?
A. customer_12
B. loop
C. customer@orgA
D. 12customer
Ans:
A
12. What is the value of customer_id within
the nested block in the example below?
/* Start
main block */
DECLARE
customer_id
NUMBER(9) := 678;
credit_limit
NUMBER(10,2) := 10000;
BEGIN
/*
Start nested block */
DECLARE
customer_id
VARCHAR2(9) := 'AP56';
current_balance
NUMBER(10,2) := 467.87;
BEGIN
-- what is
the value of customer_id at this point?
NULL;
END;
END;
Please
select the best answer.
A. 678
B. 10000
C. 'AP56'
D. 467.87
Ans:
B.
13. For which task is it best to use a
character string enclosed by double quotes? Please select the best answer.
A. Referring to a column in the database
B. Using a reserved word to declare an identifier
C. Using a hyphen to concatenate two columns
D. Referring to a number variable by using a logical operator
Ans:
B.
14. What is the maximum number of exception
handlers processed before the PL/SQL block is exited, provided an exception
occurs? Please select the best answer.
A. None
B. All exceptions that are referenced in the block
C. One
D. All exceptions that apply
Ans:
C.
15. Which functions can be used with any
datatype? Please select all the correct answers.
A. SUM
B. MIN
C. MAX
D. AVG
The
correct answers are B and C.
16. Select incorrect variable
declarations
A.
foo_number varchar2(10);
B. foo_text
number(10);
C. foo_char
char(1) := 'Y';
D. foo_time
date;
E. foo_text
varchar2(10) := 'hello world';
Ans:
E
17. Select invalid variable types
A. CHAR
B. VARCHAR1
C. VARCHAR2
D. INTEGER
E. NUMBER
ANS: B
18. List the correct sequence of commands to
process a set of records when using explicit cursors
A.
INITIALIZE, GET, CLOSE
B. CURSOR,
GET, FETCH, CLOSE
C. OPEN,
FETCH, CLOSE
D. CURSOR,
FETCH, CLOSE
E. GET,
SEEK, HIDE
ANS:
C
19. Select incorrect variable declarations
A. foo_number
varchar2(10);
B. foo_text
number(10);
C. foo_char
char(1) := 'Y';
D. foo_time
date;
E. foo_text
varchar2(10) := 'hello world';
Ans:
E
20. Select invalid variable types
A. CHAR
B. VARCHAR1
C. VARCHAR2
D. INTEGER
E. NUMBER
ANS: B
--------------------------------
21. List the correct sequence of
commands to process a set of records when using explicit cursors
A.
INITIALIZE, GET, CLOSE
B. CURSOR,
GET, FETCH, CLOSE
C. OPEN,
FETCH, CLOSE
D. CURSOR,
FETCH, CLOSE
E. GET,
SEEK, HIDE
ANS:
C
22. Where do you declare an explicit cursor
in the PL/SQL language?
A.
In the PL/SQL working storage section
B.
In the PL/SQL declaration section
C.
In the PL/SQL body section
D.
In the PL/SQL exception section
E.
None of the above
ANS: B
23.
24. The || is is an example of what
function
SELECT last_name || ', ' || first_name || ' '
|| middle_name
FROM employees;
A.
Incantination
B.
Integration
C.
Continuation
D.
Concatenation
E.
None of the above
ANS: D
25. Which of the following is not an
Oracle DML function?
A.
DECODE
B.
TRUNCATE
C.
TO_CHAR
D.
NVL
E.
Trick question, all of these are Oracle DML functio
ANS: B
26.
27. Select the best answer. Which
listed attribute is an invalid attribute of an Explicit cursor.
A.
%NOTFOUND
B.
%FOUND
C.
%ROWCOUNT
D.
%ISOPEN
E.
None of the above. All of these are valid.
ANS: E
28. Which of the following is not a
grouping function.
A.
COUNT
B.
SUM
C.
DISTINCT
D.
MIN
E.
All of the above.
ANS: C
29.
31. Select the best answer below.
What are the components of a package?
A.
Box, wrapping and binding
B.
Header and body
C.
Specification and content
D.
Specification and body
E.
None of the above
ANS: D
37. If you don't specify a mode for a
parameter, what is the default mode?
a.OUT
b.IN
c.COPY
d.DEFAULT
e.R(ead)
ANS: B
39. What are the three parameter modes for
procedures?
a.IN, OUT,
IN OUT
b.R(ead),
W(rite), A(ppend)
c.CONSTANT,
VARIABLE, DEFAULT
d.COPY,
NOCOPY, REF
ANS: A
41. What is the correct syntax to create procedure MYPROC
that accepts two number parameters X and Y?
a.CREATE PROCEDURE myproc (x NUMBER, y NUMBER) IS ...
b.CREATE PROCEDURE (x NUMBER, y NUMBER) myproc IS ...
c.CREATE PROCEDURE myproc IS (x NUMBER, y NUMBER) ...
d.CREATE PROCEDURE IS myproc (x NUMBER, y NUMBER) ...
ANS: A
----------------------------------------------------------
40. Which one of the following statements
about formal and actual parameters is true?
a.Formal
and actual parameters must have the same name.
b.Formal and actual parameters must have different names.
c.A formal parameter is declared within the called procedure,
while an actual parameter is declared in thecalling environment.
d.An actual parameter is declared within the called
procedure.
ANS: C
42. In the context of
MS SQL SERVER, with the exception of ............ column(s), any column can
participate in the GROUP BY clause.
A) bit
B) text
C) ntext
D) image
E) All of above
ANS: E
32. PL/SQL
subprograms, unlike anonymous blocks, are compiled each time they are executed.
True or False?
a. True
b.False
ANS: A
38. Which kind of parameters cannot have a
DEFAULT value?
a.OUT
b.IN
c.CONSTANT
d.R(ead)
e.W(rite)
ANS: A
33. Subprograms and anonymous blocks can be called
by other applications. True or False?
a.True
b.False
ANS: A
Select the
invalid PL/SQL looping construct.
A.
WHILE LOOP
...
END LOOP;
B.
FOR rec IN some_cursor LOOP
...
END LOOP;
C.
LOOP
...
UNTIL ;
END LOOP;
D.
LOOP
...
EXIT WHEN ;
END LOOP;
E.
None of the above. All are valid.
ANS: C.D
34. A nested subprogram can be called from
the main procedure or from the calling environment. Trueor False?
a. True
b. False
ANS: B
Which of the following is not a valid Oracle
PL/SQL exception.
A.
NO_DATA_FOUND ORA-01403
B.
TWO_MANY_ROWS ORA-01422
C.
DUP_VAL_ON_INDEX ORA-00001
D.
OTHERS
E.
None of the above. These are all valid.
ANS: B
Assuming the
date and time is 09/09/2009 09:09:09, what value will the following statement
return SELECT TO_CHAR(TRUNC(SYSDATE),'MM/DD/YYYY HH24:MI:SS') FROM dual;
A.
09/09/2009 09:09:09
B.
09/09/2009 09:09:09AM
C.
09/09/2009
D.
09/09/2009 00:00:00
E.
None of the above
ANS: D
35. When modifying procedure code, the
procedure must be re-executed to validate and store it in the database. True or
False?
a. True
b. False
ANS: A
36. Which of the following can be used as an
argument for a procedure parameter?
a.The name
of a variable.
b.A literal
value.
c.An
expression.
d.All of
the above.
e.None of
the above
ANS: D
43. The sequence of the
columns in a GROUP BY clause has no effect in the ordering of the output.
A) True
B) False
ANS: B
44. You want all
dates when any employee was hired. Multiple employees were hired on the same
date and you want to see the date only once.
Query - 1
Select distinct hiredate
From hr.employee
Order by hiredate;
Query - 2
Select hiredate
From hr.employees
Group by hiredate
Order by hiredate;
Which of the above query is valid?
A) Query - 1
B) Query - 2
C) Both
ANS: C
45. GROUP BY ALL
generates all possible groups - even those that do not meet the query's search
criteria.
A) True
B) False
ANS: A
46. All aggregate
functions ignore NULLs except for ............
A) Distinct
B) Count (*)
C) Average()
D) None of above
ANS: B
47. Using GROUP BY ............
has the effect of removing duplicates from the data.
A) with aggregates
B) with order by
C) without order by
D) without aggregates
ANS: D
48. Below query is
run in SQL Server 2012, is this query valid or invalid:
Select count(*) as X
from Table_Name
Group by ()
A) Valid
B) Invalid
ANS: A
49. For the purposes
of ............, null values are considered equal to other nulls and are
grouped together into a single result row.
A) Having
B) Group By
C) Both of above
D) None of above
ANS: B
50. If you SELECT
attributes and use an aggregate function, you must GROUP BY the non-aggregate
attributes.
A) True
B) False
ANS: A
1. Collections of operations that form a single logical unit of
work are called __________
a) Views
b) Networks
c) Units
d) Transactions
View Answer
Answer: d
Explanation: Collections of
operations that form a single logical unit of work are called transactions. A
database system must ensure proper execution of transactions.
2. The “all-or-none” property is commonly referred to as _________
a) Isolation
b) Durability
c) Atomicity
d) None of the mentioned
View Answer
Answer: c
Explanation: The all or none
policy is commonly referred to as atomicity. It ensures that a work is either
completed or not completed and there are no intermediate stages.
3. Which of the following is a property of transactions?
a) Atomicity
b) Durability
c) Isolation
d) All of the mentioned
View Answer
Answer: d
Explanation: Atomicity,
Durability and Isolation are all properties of transactions.
4. Execution of translation in isolation preserves the _________ of
a database
a) Atomicity
b) Consistency
c) Durability
d) All of the mentioned
View Answer
Answer: b
Explanation: Execution of
translation in isolation preserves the consistency of a database. It ensures
that no other transaction is running concurrently.
5. Which of the following is not a property of a transaction?
a) Atomicity
b) Simplicity
c) Isolation
d) Durability
View Answer
Answer: b
Explanation: Simplicity is not a
property of a transaction. Atomicity, Isolation, Durability are all parts of
ACID properties.
6. Which of the following systems is responsible for ensuring
durability?
a) Recovery system
b) Atomic system
c) Concurrency control system
d) Compiler system
View Answer
Answer: a
Explanation: The recovery system
is responsible for the maintenance of durability. In addition, it also ensures
atomicity.
7. Which of the following systems is responsible for ensuring
isolation?
a) Recovery system
b) Atomic system
c) Concurrency control system
d) Compiler system
View Answer
Answer: c
Explanation: The concurrency
control system is responsible for ensuring isolation in a database system.
9. A transaction that has not been completed successfully is called
as _______
a) Compensating transaction
b) Aborted transaction
c) Active transaction
d) Partially committed transaction
View Answer
Answer: b
Explanation: Aborted transaction
is a state after the transaction has been rolled back and the database has been
restored to the state prior to the transaction.
10. Which of the following is not a transaction state?
a) Active
b) Partially committed
c) Failed
d) Compensated
View Answer
Answer: d
Explanation: Compensated is not a
transaction state. But active, partially committed and failed are different
states of a transaction.
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11. The execution sequences in concurrency control are termed as
________
a) Serials
b) Schedules
c) Organizations
d) Time tables
View Answer
Answer: b
Explanation: The execution
sequences in concurrency control are known as schedules.
12. The scheme that controls the interaction between executing
transactions is called as _____
a) Concurrency control scheme
b) Multiprogramming scheme
c) Serialization scheme
d) Schedule scheme
View Answer
Answer: a
Explanation: The scheme that
controls the interaction between executing transactions is called as
concurrency control scheme.
1. I and J are _________ if they are
operations by different transactions on the same data item, and at least one of
them is a write operation.
a) Conflicting
b) Overwriting
c) Isolated
d) Durable
View
Answer
Answer:
a
Explanation:
I and J are conflicting if they are operations by different transactions on the
same data item, and at least one of them is a write operation.
2. If a schedule S can be transformed into a
schedule S’ by a series of swaps of non-conflicting instructions, then S and S’
are
a) Non conflict equivalent
b) Equal
c) Conflict equivalent
d) Isolation equivalent
View
Answer
Answer:
c
Explanation:
If a schedule S can be transformed into a schedule S’ by a series of swaps of
non-conflicting instructions, then S and S’ are conflict equivalent. Not all
serial schedules are conflict equivalent to each other.
3. A schedule is __________ if it is conflict
equivalent to a serial schedule.
a) Conflict serializable
b) Conflicting
c) Non serializable
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
A schedule is conflict serializable if it is conflict equivalent to a serial
schedule. The concept of conflict equivalence leads to the concept.
4. The set of ________ in a precedence graph
consists of all the transactions participating in the schedule
a) Vertices
b) Edges
c) Directions
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
The set of vertices in a precedence graph consists of all the transactions
participating in the schedule. Precedence graph is a simple and efficient way
of determining conflict serializability of the schedule.
-------------------------------------------------------------------------
5. A ___________of the transactions can be
obtained by finding a linear order consistent with the partial order of the
precedence graph.
a) Serializability order
b) Direction graph
c) Precedence graph
d) Scheduling scheme
View
Answer
Answer:
a
Explanation:
A Serializability order of the transactions can be obtained by finding a linear
order consistent with the partial order of the precedence graph. This process
is called as topological sorting.
6. State true or false: If I = read(Q) and J =
read(Q) then the order of I and J does not matter.
a) True
b) False
View
Answer
Answer:
a
Explanation:
If I = read(Q) and J = read(Q) then the order of I and J does not matter
because both I and J are read operations on the query.
State true or false: Information residing
in the volatile storage does not usually survive system crashes
a) True
b) False
View Answer
Answer: a
7. State true or false: If I = read(Q) and J =
write(Q) then the order of I and J does not matter.
a) True
b) False
View
Answer
Answer:
b
Explanation:
If I = read(Q) and J = write(Q) then the order of I and J matters because both
I and J are different operations on the query. The order of execution
determines the state of the database that is being read or written.
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1. If a transaction has obtained a __________
lock, it can read but cannot write on the item
a) Shared mode
b) Exclusive mode
c) Read only mode
d) Write only mode
View
Answer
Answer:
a
Explanation:
If a transaction Ti has obtained a shared-mode lock (denoted by S) on item Q,
then Ti can read, but cannot write, Q.
2. If a transaction has obtained a ________
lock, it can both read and write on the item
a) Shared mode
b) Exclusive mode
c) Read only mode
d) Write only mode
View
Answer
Answer:
b
Explanation:
If a transaction has obtained an exclusive mode lock, then it can both read and
write on the item on which it in operating.
3. A transaction can proceed only after the
concurrency control manager ________ the lock to the transaction
a) Grants
b) Requests
c) Allocates
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
A transaction can proceed only after the concurrency control manager grants the
lock to the transaction.
4. If a transaction can be granted a lock on
an item immediately in spite of the presence of another mode, then the two
modes are said to be ________
a) Concurrent
b) Equivalent
c) Compatible
d) Executable
View
Answer
Answer:
c
Explanation:
If a transaction can be granted a lock on an item immediately in spite of the
presence of another mode, then the two modes are said to be compatible.
7. The situation where no transaction can
proceed with normal execution is known as ________
a) Road block
b) Deadlock
c) Execution halt
d) Abortion
View
Answer
Answer:
b
Explanation:
The situation where no transaction can proceed with normal execution is known
as a deadlock.
10. The two phase locking protocol consists which
of the following phases?
a) Growing phase
b) Shrinking phase
c) both a,b
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
The two phased locking protocol consists of the growing phase and the shrinking
phase.
1.
2. Which of the following is not a method in
deadlock handling
a) Deadlock prevention
b) Deadlock detection
c) Deadlock recovery
d) Deadlock distribution
View
Answer
Answer:
d
Explanation:
Deadlock distribution is not a method in deadlock handling whereas, deadlock
prevention is followed by deadlock detection and deadlock recovery.
3. Deadlocks can be prevented using
a) Preemption and transaction rollbacks
b) Wait and die scheme
c) Wound-wait scheme
d) All of the mentioned
View
Answer
Answer:
d
Explanation:
Preemption and transaction rollbacks, wait and die scheme, wound wait scheme
are all different methods of deadlock prevention.
4. State true or false: Wait die scheme is a
non-preemptive technique
a) True
b) False
View
Answer
Answer:
a
Explanation:
The wait-die scheme is a non-preemptive technique. When transaction Ti requests
a data item currently held by Tj , Ti is allowed to wait only if it has a timestamp
smaller than that of Tj (that is, Ti is older than Tj ). Otherwise, Ti is
rolled back (dies).
5.
6. The _________ graph describes deadlocks
precisely
a) Wound wait graph
b) Wait die graph
c) Wait for graph
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
The wait for graph describes deadlocks precisely. Existence of a cycle in this
graph implies that a deadlock will occur.
7. How do we generally recover from a
deadlock?
a) By aborting all the transactions
b) By rolling back all the transactions
c) By rolling back only a selected number of
transactions
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
We generally recover from deadlocks by rolling back only a selected number of
transactions
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8. State true or false: Partial rollback is
not possible.
a) True
b) False
View
Answer
Answer:
b
Explanation:
Partial rollback is possible but it requires the system too maintain an
additional amount of information on the states of the transactions.
9. Which of the following steps must be taken
while choosing a victim?
a) Avoiding starvation
b) Number of transactions involved in rollback
c) Data items used by the transaction
d) All of the mentioned
View
Answer
Answer:
d
Explanation:
While choosing a victim we much choose the one with a minimum cost. That is the
one which avoids starvation, the one with the least number of transaction
involved in the rollback and the one with the least amount of data items used.
7.
9. In timestamp ordering protocol, suppose
that the transaction Ti issues read(Q) and TS(Ti)<W-timestamp(Q), then
a) Read operation is executed
b) Read operation is rejected
c) Write operation is executed
d) Write operation is rejected
View
Answer
Answer:
b
1. The _________ requires each transaction
executes in two or three different phases in its lifetime
a) Validation protocol
b) Timestamp protocol
c) Deadlock protocol
d) View protocol
View
Answer
Answer:
a
Explanation:
The validation protocol requires each transaction to execute in two or three
different phases in its lifetime depending on whether it is a read only or an
update transaction.
2. During __________ phase, the system reads
data and stores them in variables local to the transaction.
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
During the read phase, the system reads data and stores them in variables local
to the transaction. It performs all write operations on temporary local
variables without updates on the actual database.
3. During the _________ phase the validation
test is applied to the transaction
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View
Answer
Answer:
b
Explanation:
During the validation phase, the validation test is applied to the transaction.
This determines whether the transaction is allowed to proceed or not without
causing a violation of serializability.
4. During the _______ phase, the local variables
that hold the write operations are copied to the database
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
During the write phase, the local variables that hold the write operations are
copied to the database. Read only operations omit this phase.
1) Which of
the following is not a recovery technique?
A. Deferred
update
B. Immediate
update
C. Two-phase
commit
D. Recovery
management
2)Checkpoints
are a part of
A. Recovery measures
B. Security measures
C. Concurrency measures
D. Authorization measures
3) .......
deals with soft errors, such as power failures.
A. system
recovery
B. media
recovery
C. database
recovery
D. failure
recovery
4)
........... is an essential part of any backup system.
A. Filter
B. Recovery
C. Security
D.
Scalability
5) Media
recovery deals with ...........
A. disk
errors
B. hard
errors
C. system
errors
D. power
failures
6) For a
backup/restore system, ............. is a prerequisite for service in a
enterprise.
A. Filter
B. Recovery
C. Security
D.
Scalability
7) Failure
recovery and media recovery fall under ........
A.
transaction recovery
B. database
recovery
C. system
recovery
D. value
recovery
9) In which
the database can be restored up to the last consistent state after the system
failure?
A. Backup
B. Recovery
C. Both
D. None
11) In log
based recovery, the log is sequence of .........
A. filter
B. records
C. blocks
E. numbers
13)
.......... is an alternative of log based recovery.
A. Disk
recovery
B. Shadow
paging
C. Dish
shadowing
D. Crash
recovery
-------------------------------------------------------------------------------------------------------------------
10) A
........... is a block of Recovery Manager(RMAN)job commands that is stored in
the recovery catalogue.
A. recovery
procedure
B. recovery
block
C. stored
block
D. stored
script
12) The
enrolling of a database in a recovery catalogue is called .........
A. set up
B. registration
C. start up
D. enrolment
14) Most
backup and recovery commands in ........... are executed by server sessions.
A. Backup
Manager
B. Recovery
Manager
C. Backup
and Recovery Manager
D. Database
Manager
15) ........
systems typically allows to replace failed disks without stopping access to the
system.
A. RAM
B. RMAN
C. RAD
D. RAID
16) An
......... is an exact copy of a single datafile, archived redo log file, or
control file.
A. image
copy
B. datafile
copy
C. copy log
D. control
copy
17)
.......... known as memory-style error correcting-code(ECC) organization,
employs parity bits.
A. RAID
level 1
B. RAID
level 2
C. RAID
level 3
D. RAID
level 4
18) The
remote backup site is sometimes called the .......... site.
A. primary
B. secondary
C. ternary
D. None of
the above
19) EXP
command is used ...........
A. to take
Backup of the Oracle Database
B. to import
data from the exported dump file
C. to create
Rollback segments
D. to create
Schedule.
20) The
simplest approach to introducing redundancy is to duplicate every disk is
called .....
A. mirroring
B. imaging
C. copying
D. All of
the above
Answers:
1) C.
Two-phase commit
2) A.
Recovery measures
3) D.
failure recovery
4) C.
Security
5) A. disk
errors
6) D.
Scalability
7) C. system
recovery
8) A.
Recovery Manager environment
9) B.
Recovery
10) D.
stored script
11) B.
records
12) B.
registration
13) B.
Shadow paging
14) B.
Recovery Manager
15) D. RAID
16) A. image
copy
17) B. RAID
level 2
18) B.
secondary
19) A. to
take Backup of the Oracle Database
20) A.
mirroring
5. A transaction is made to wait until all
________ locks held on the item are released
a) Compatible
b) Incompatible
c) Concurrent
d) Equivalent
View
Answer
Answer:
a
Explanation:
A transaction is made to wait until all compatible locks held on the item are
released. This ensures that no other transaction is concurrently accessing the
same item.
6. State true or false: It is not necessarily
desirable for a transaction to unlock a data item immediately after its final
access
a) True
b) False
View
Answer
Answer:
a
Explanation:
It is not necessarily desirable for a transaction to unlock a data item
immediately after its final access because serializability may be violated due
to this.
8. The protocol that indicates when a
transaction may lock and unlock each of the data items is called as __________
a) Locking protocol
b) Unlocking protocol
c) Granting protocol
d) Conflict protocol
View
Answer
Answer:
a
Explanation:
The protocol that indicates when a transaction may lock and unlock each of the
data items is called as locking protocol. Locking protocols restrict the number
of schedules.
9. If a transaction Ti may never make
progress, then the transaction is said to be ____________
a) Deadlocked
b) Starved
c) Committed
d) Rolled back
View
Answer
A
system is in a _______ state if there exists a set of transactions in which
every transaction is waiting for another transaction in the set.
a) Deadlock
b) Starved
c) Isolated
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
A system is in a deadlock state if there exists a set of transactions in which
every transaction is waiting for another transaction in the set.
Lock
timeouts have which of the following advantages?
a) Unnecessary rollbacks do not occur
b) Transactions do not starve
c) It is easy to implement
d) All of the mentioned
View
Answer
Answer:
d
Explanation:
In lock timeout method, unnecessary rollbacks do not occur, transactions do not
starve and it is also easy to implement and is hence widely used if
transactions are short and long waits are likely to be due to deadlocks.
State true or false: The Thomas write
rule has a greater potential concurrency than the timestamp ordering protocol
a) True
b) False
View
Answer
Answer:
a
Explanation:
The Thomas write rule has a greater potential concurrency than the timestamp
ordering protocol. This is because it is a modified version of the timestamp
ordering protocol in which obsolete write operations can be ignored under certain
circumstances.
8. Which of the following timestamp based
protocols generates serializable schedules?
a) Thomas write rule
b) Timestamp ordering protocol
c) Validation protocol
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
Thomas write rule protocol generates serializable schedules that no other
protocol can generate.
Explanation:
Suppose that transaction Ti issues read(Q). If TS(Ti ) < W-timestamp(Q),
then Ti needs to read a value of Q that was already overwritten. Hence, the
read operation is rejected, and Ti is rolled back.
10. In timestamp ordering protocol, suppose that
the transaction Ti issues write(Q) and TS(Ti)<W-timestamp(Q), then
a) Read operation is executed
b) Read operation is rejected
c) Write operation is executed
d) Write operation is rejected
View
Answer
Answer:
d
Explanation:
In timestamp ordering protocol, suppose that the transaction Ti issues write(Q)
and TS(Ti)<W-timestamp(Q), then the value of Q that Ti is producing was
needed previously, and the system assumed that the value would never be
produced. Hence the system rejects the write(Q) operation and t
5. Read only operations omit the _______ phase
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
Read only operations do not allow write operation to be performed on them. So,
they omit the write phase but execute the read and validation phases.
6. Which of the following timestamp is used to
record the time at which the transaction started execution?
a) Start(i)
b) Validation(i)
c) Finish(i)
d) Write(i)
View
Answer
Answer:
a
Explanation:
There are three different timestamps for each transaction start(i),
validation(i), finish(i). Start(i) is used to record the time at which the
transaction execution started.
8) The
.......... consists of the various applications and database that play a role
in a backup and recovery strategy.
A. Recovery
Manager environment
B. Recovery
Manager suit
C. Recovery
Manager file
D. Recovery
Manager database
1. MCQ:
In the relational model, the row of the table is known to be
A. Relation
B.
Attribute
C. Tuple
D. Entity field
Answer
2. MCQ:
Relational model eases the job of the programmer, compared to earlier data
models such as
A. Network model
B.
Hierarchical model
C.
Semistructured model
D. Both A and B
Answer
3. MCQ:
To refer to a specific instance of a relation in the relational model, the term
used is known as
A. Relation instance
B.
Relation entity
C.
Relation tuple
D. Relation attribute
Answer
4. MCQ:
A property of the entire relation, rather than of the individual tuples, is
known as
A. Attribute
B.
Constant
C.
Variable
D. Key
Answer
Answer
Answer
5. MCQ:
Minimal superkeys are called
A. Unique key
B.
Superset key
C. Candidate key
D. Primary key
Answer
6. MCQ:
A table is a collection of relationships, there is a close correspondence
between the concept of
A. Tables and instances
B.
Tables and Entries
C.
Table and variables
D. Tables and relations
Answer
7. MCQ:
The term that says values appearing in specified attributes of any tuple in the
referencing relation also appear in specified attributes of at least one tuple
in the referenced relation, is called
A. Constant Integrity constraint
B.
Variable Integrity constraint
C. Referential Integrity
constraint
D. Attribute Integrity constraint
Answer
8. MCQ:
A relation, say r1, may include among its attributes the primary key of another
relation, say r2. the r1 is also known as
A. Parent relation
B.
Referenced relation
C. Referencing relation
D. Node relation
9. MCQ:
In the relational model, the column of the table is known to be
A. Entity field
B. Attribute
C.
Tuple
D. Relation
a. Answer
10.
MCQ: The contents of a relation instance may change
with time as the relation
A. Domain
B.
Time
C. Updated
D. Retrieved
Answer
11.
MCQ: The query languages are usually on a level higher
than that of a standard
A. Updation language
B.
Query program language
C.
Procedural language
D. Programming language
Answer
12.
MCQ: Query languages used in practice includes
A. Elements
B.
Fields
C.
Instances
D. Tuples
Answer
13.
MCQ: A set of one or more attributes that
collectively, allow us to identify uniquely a tuple in the relation, is known
as
A. Unique key
B.
Special key
C. Super key
D. Primary key
14.
MCQ: A relation schema consists of a list of
attributes and their corresponding
A. Variables
B.
Instances
C. Domains
D. Tuples
Answer
15.
MCQ: A row in a table represents a relationship among
a
A. Procedures
B. Set of values
C.
Sequence of values
D. Entities
Answer
16.
MCQ: The logical design of the database, is known to
be
A. Database instance
B.
Database entity
C.
Database relation
D. Database Schema
Answer
17.
MCQ: The type of query in which user describes the
desired information without giving a specific procedure for obtaining that
information, is known to be
A. Procedural language
B. Nonprocedural
language
C.
Programming language
D. Query program
18.
MCQ: The address field of a person should not be part
of the primary key, since it is likely to
A. Dependent
B. Changed
C.
Not changed
D. Too long
19.
MCQ: The primary key should be chosen such that its
attribute values are
A. Updated
B.
Dependent
C.
Changed
D. Never changed
20.
MCQ: The user instructs the system to perform a
sequence of operations on the database to compute the desired outcome, is known
as
A. Programming language
B.
Query program
C. Procedural language
D. Nonprocedural language
Answer
21.
MCQ: The relational model is today the primary data
model for commercial
A. Data management applications
B.
Data storage applications
C. Data processing
applications
D. Data program application
Answer
22.
MCQ: The query language is a language in which a user
A. Requests
B.
Response
C.
Stores
D. Represents
Answer
23.
MCQ: A snapshot of the data in the database at a given
instant in time, is known as
A. Database entity
B.
Database relation
C. Database instance
D. Database Schema
Answer
24.
MCQ: We are often interested in superkeys for which no
proper subset is a
A. Superset key
B. Superkey
C.
Primary key
D. Unique key
U
1. Which of the following statements is true
about implicit cursors?
A. Implicit
cursors are used for SQL statements that are not named.
B.
Developers should use implicit cursors with great care.
C. Implicit
cursors are used in cursor for loops to handle data processing.
D. Implicit
cursors are no longer a feature in Oracle.
Ans: A
2. Which of the following is not a feature of
a cursor FOR loop?
A. Record
type declaration.
B. Opening
and parsing of SQL statements.
C. Fetches
records from cursor.
D. Requires
exit condition to be defined.
Ans:B
3. A developer would like to use referential
datatype declaration on a variable. The variable name is EMPLOYEE_LASTNAME, and
the corresponding table and column is EMPLOYEE, and LNAME, respectively. How
would the developer define this variable using referential datatypes?
A. Use
employee.lname%type.
B. Use
employee.lname%rowtype.
C. Look up
datatype for EMPLOYEE column on LASTNAME table and use that.
D. Declare
it to be type LONG.
Ans: A
4. Which three of the following are implicit
cursor attributes?
A. %found
B.
%too_many_rows
C.
%notfound
D.
%rowcount
E. %rowtype
Ans:C
5. If left out, which of the following would
cause an infinite loop to occur in a simple loop?
A. LOOP
B. END LOOP
C. IF-THEN
D. EXIT
Ans:B
6. Which line in the following statement will
produce an error?
A. cursor
action_cursor is
B. select
name, rate, action
C. into
action_record
D. from
action_table;
E. There
are no errors in this statement.
Ans:C
7. The command used to open a CURSOR FOR loop
is
A. open
B. fetch
C. parse
D. None,
cursor for loops handle cursor opening implicitly.
Ans:D
8. What happens when rows are found using a
FETCH statement
A. It
causes the cursor to close
B. It
causes the cursor to open
C. It loads
the current row values into variables
D. It
creates the variables to hold the current row values
Ans: B
9. What is the maximum number of handlers
processed before the PL/SQL block is exited when an exception occurs?
A. Only one
B. All that
apply
C. All
referenced
D. None
Ans: A
10. For which trigger timing can you
reference the NEW and OLD qualifiers?
A.
Statement and Row
B.
Statement only
C. Row only
D. Oracle
Forms trigger
Ans: D
11. Which identifier is valid?
A. customer_12
B. loop
C. customer@orgA
D. 12customer
Ans:
A
12. What is the value of customer_id within
the nested block in the example below?
/* Start
main block */
DECLARE
customer_id
NUMBER(9) := 678;
credit_limit
NUMBER(10,2) := 10000;
BEGIN
/*
Start nested block */
DECLARE
customer_id
VARCHAR2(9) := 'AP56';
current_balance
NUMBER(10,2) := 467.87;
BEGIN
-- what is
the value of customer_id at this point?
NULL;
END;
END;
Please
select the best answer.
A. 678
B. 10000
C. 'AP56'
D. 467.87
Ans:
B.
13. For which task is it best to use a
character string enclosed by double quotes? Please select the best answer.
A. Referring to a column in the database
B. Using a reserved word to declare an identifier
C. Using a hyphen to concatenate two columns
D. Referring to a number variable by using a logical operator
Ans:
B.
14. What is the maximum number of exception
handlers processed before the PL/SQL block is exited, provided an exception
occurs? Please select the best answer.
A. None
B. All exceptions that are referenced in the block
C. One
D. All exceptions that apply
Ans:
C.
15. Which functions can be used with any
datatype? Please select all the correct answers.
A. SUM
B. MIN
C. MAX
D. AVG
The
correct answers are B and C.
16. Select incorrect variable
declarations
A.
foo_number varchar2(10);
B. foo_text
number(10);
C. foo_char
char(1) := 'Y';
D. foo_time
date;
E. foo_text
varchar2(10) := 'hello world';
Ans:
E
17. Select invalid variable types
A. CHAR
B. VARCHAR1
C. VARCHAR2
D. INTEGER
E. NUMBER
ANS: B
18. List the correct sequence of commands to
process a set of records when using explicit cursors
A.
INITIALIZE, GET, CLOSE
B. CURSOR,
GET, FETCH, CLOSE
C. OPEN,
FETCH, CLOSE
D. CURSOR,
FETCH, CLOSE
E. GET,
SEEK, HIDE
ANS:
C
19. Select incorrect variable declarations
A. foo_number
varchar2(10);
B. foo_text
number(10);
C. foo_char
char(1) := 'Y';
D. foo_time
date;
E. foo_text
varchar2(10) := 'hello world';
Ans:
E
20. Select invalid variable types
A. CHAR
B. VARCHAR1
C. VARCHAR2
D. INTEGER
E. NUMBER
ANS: B
--------------------------------
21. List the correct sequence of
commands to process a set of records when using explicit cursors
A.
INITIALIZE, GET, CLOSE
B. CURSOR,
GET, FETCH, CLOSE
C. OPEN,
FETCH, CLOSE
D. CURSOR,
FETCH, CLOSE
E. GET,
SEEK, HIDE
ANS:
C
22. Where do you declare an explicit cursor
in the PL/SQL language?
A.
In the PL/SQL working storage section
B.
In the PL/SQL declaration section
C.
In the PL/SQL body section
D.
In the PL/SQL exception section
E.
None of the above
ANS: B
23.
24. The || is is an example of what
function
SELECT last_name || ', ' || first_name || ' '
|| middle_name
FROM employees;
A.
Incantination
B.
Integration
C.
Continuation
D.
Concatenation
E.
None of the above
ANS: D
25. Which of the following is not an
Oracle DML function?
A.
DECODE
B.
TRUNCATE
C.
TO_CHAR
D.
NVL
E.
Trick question, all of these are Oracle DML functio
ANS: B
26.
27. Select the best answer. Which
listed attribute is an invalid attribute of an Explicit cursor.
A.
%NOTFOUND
B.
%FOUND
C.
%ROWCOUNT
D.
%ISOPEN
E.
None of the above. All of these are valid.
ANS: E
28. Which of the following is not a
grouping function.
A.
COUNT
B.
SUM
C.
DISTINCT
D.
MIN
E.
All of the above.
ANS: C
29.
31. Select the best answer below.
What are the components of a package?
A.
Box, wrapping and binding
B.
Header and body
C.
Specification and content
D.
Specification and body
E.
None of the above
ANS: D
37. If you don't specify a mode for a
parameter, what is the default mode?
a.OUT
b.IN
c.COPY
d.DEFAULT
e.R(ead)
ANS: B
39. What are the three parameter modes for
procedures?
a.IN, OUT,
IN OUT
b.R(ead),
W(rite), A(ppend)
c.CONSTANT,
VARIABLE, DEFAULT
d.COPY,
NOCOPY, REF
ANS: A
41. What is the correct syntax to create procedure MYPROC
that accepts two number parameters X and Y?
a.CREATE PROCEDURE myproc (x NUMBER, y NUMBER) IS ...
b.CREATE PROCEDURE (x NUMBER, y NUMBER) myproc IS ...
c.CREATE PROCEDURE myproc IS (x NUMBER, y NUMBER) ...
d.CREATE PROCEDURE IS myproc (x NUMBER, y NUMBER) ...
ANS: A
----------------------------------------------------------
40. Which one of the following statements
about formal and actual parameters is true?
a.Formal
and actual parameters must have the same name.
b.Formal and actual parameters must have different names.
c.A formal parameter is declared within the called procedure,
while an actual parameter is declared in thecalling environment.
d.An actual parameter is declared within the called
procedure.
ANS: C
42. In the context of
MS SQL SERVER, with the exception of ............ column(s), any column can
participate in the GROUP BY clause.
A) bit
B) text
C) ntext
D) image
E) All of above
ANS: E
32. PL/SQL
subprograms, unlike anonymous blocks, are compiled each time they are executed.
True or False?
a. True
b.False
ANS: A
38. Which kind of parameters cannot have a
DEFAULT value?
a.OUT
b.IN
c.CONSTANT
d.R(ead)
e.W(rite)
ANS: A
33. Subprograms and anonymous blocks can be called
by other applications. True or False?
a.True
b.False
ANS: A
Select the
invalid PL/SQL looping construct.
A.
WHILE LOOP
...
END LOOP;
B.
FOR rec IN some_cursor LOOP
...
END LOOP;
C.
LOOP
...
UNTIL ;
END LOOP;
D.
LOOP
...
EXIT WHEN ;
END LOOP;
E.
None of the above. All are valid.
ANS: C.D
34. A nested subprogram can be called from
the main procedure or from the calling environment. Trueor False?
a. True
b. False
ANS: B
Which of the following is not a valid Oracle
PL/SQL exception.
A.
NO_DATA_FOUND ORA-01403
B.
TWO_MANY_ROWS ORA-01422
C.
DUP_VAL_ON_INDEX ORA-00001
D.
OTHERS
E.
None of the above. These are all valid.
ANS: B
Assuming the
date and time is 09/09/2009 09:09:09, what value will the following statement
return SELECT TO_CHAR(TRUNC(SYSDATE),'MM/DD/YYYY HH24:MI:SS') FROM dual;
A.
09/09/2009 09:09:09
B.
09/09/2009 09:09:09AM
C.
09/09/2009
D.
09/09/2009 00:00:00
E.
None of the above
ANS: D
35. When modifying procedure code, the
procedure must be re-executed to validate and store it in the database. True or
False?
a. True
b. False
ANS: A
36. Which of the following can be used as an
argument for a procedure parameter?
a.The name
of a variable.
b.A literal
value.
c.An
expression.
d.All of
the above.
e.None of
the above
ANS: D
43. The sequence of the
columns in a GROUP BY clause has no effect in the ordering of the output.
A) True
B) False
ANS: B
44. You want all
dates when any employee was hired. Multiple employees were hired on the same
date and you want to see the date only once.
Query - 1
Select distinct hiredate
From hr.employee
Order by hiredate;
Query - 2
Select hiredate
From hr.employees
Group by hiredate
Order by hiredate;
Which of the above query is valid?
A) Query - 1
B) Query - 2
C) Both
ANS: C
45. GROUP BY ALL
generates all possible groups - even those that do not meet the query's search
criteria.
A) True
B) False
ANS: A
46. All aggregate
functions ignore NULLs except for ............
A) Distinct
B) Count (*)
C) Average()
D) None of above
ANS: B
47. Using GROUP BY ............
has the effect of removing duplicates from the data.
A) with aggregates
B) with order by
C) without order by
D) without aggregates
ANS: D
48. Below query is
run in SQL Server 2012, is this query valid or invalid:
Select count(*) as X
from Table_Name
Group by ()
A) Valid
B) Invalid
ANS: A
49. For the purposes
of ............, null values are considered equal to other nulls and are
grouped together into a single result row.
A) Having
B) Group By
C) Both of above
D) None of above
ANS: B
50. If you SELECT
attributes and use an aggregate function, you must GROUP BY the non-aggregate
attributes.
A) True
B) False
ANS: A
1. Collections of operations that form a single logical unit of
work are called __________
a) Views
b) Networks
c) Units
d) Transactions
View Answer
Answer: d
Explanation: Collections of
operations that form a single logical unit of work are called transactions. A
database system must ensure proper execution of transactions.
2. The “all-or-none” property is commonly referred to as _________
a) Isolation
b) Durability
c) Atomicity
d) None of the mentioned
View Answer
Answer: c
Explanation: The all or none
policy is commonly referred to as atomicity. It ensures that a work is either
completed or not completed and there are no intermediate stages.
3. Which of the following is a property of transactions?
a) Atomicity
b) Durability
c) Isolation
d) All of the mentioned
View Answer
Answer: d
Explanation: Atomicity,
Durability and Isolation are all properties of transactions.
4. Execution of translation in isolation preserves the _________ of
a database
a) Atomicity
b) Consistency
c) Durability
d) All of the mentioned
View Answer
Answer: b
Explanation: Execution of
translation in isolation preserves the consistency of a database. It ensures
that no other transaction is running concurrently.
5. Which of the following is not a property of a transaction?
a) Atomicity
b) Simplicity
c) Isolation
d) Durability
View Answer
Answer: b
Explanation: Simplicity is not a
property of a transaction. Atomicity, Isolation, Durability are all parts of
ACID properties.
6. Which of the following systems is responsible for ensuring
durability?
a) Recovery system
b) Atomic system
c) Concurrency control system
d) Compiler system
View Answer
Answer: a
Explanation: The recovery system
is responsible for the maintenance of durability. In addition, it also ensures
atomicity.
7. Which of the following systems is responsible for ensuring
isolation?
a) Recovery system
b) Atomic system
c) Concurrency control system
d) Compiler system
View Answer
Answer: c
Explanation: The concurrency
control system is responsible for ensuring isolation in a database system.
9. A transaction that has not been completed successfully is called
as _______
a) Compensating transaction
b) Aborted transaction
c) Active transaction
d) Partially committed transaction
View Answer
Answer: b
Explanation: Aborted transaction
is a state after the transaction has been rolled back and the database has been
restored to the state prior to the transaction.
10. Which of the following is not a transaction state?
a) Active
b) Partially committed
c) Failed
d) Compensated
View Answer
Answer: d
Explanation: Compensated is not a
transaction state. But active, partially committed and failed are different
states of a transaction.
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11. The execution sequences in concurrency control are termed as
________
a) Serials
b) Schedules
c) Organizations
d) Time tables
View Answer
Answer: b
Explanation: The execution
sequences in concurrency control are known as schedules.
12. The scheme that controls the interaction between executing
transactions is called as _____
a) Concurrency control scheme
b) Multiprogramming scheme
c) Serialization scheme
d) Schedule scheme
View Answer
Answer: a
Explanation: The scheme that
controls the interaction between executing transactions is called as
concurrency control scheme.
1. I and J are _________ if they are
operations by different transactions on the same data item, and at least one of
them is a write operation.
a) Conflicting
b) Overwriting
c) Isolated
d) Durable
View
Answer
Answer:
a
Explanation:
I and J are conflicting if they are operations by different transactions on the
same data item, and at least one of them is a write operation.
2. If a schedule S can be transformed into a
schedule S’ by a series of swaps of non-conflicting instructions, then S and S’
are
a) Non conflict equivalent
b) Equal
c) Conflict equivalent
d) Isolation equivalent
View
Answer
Answer:
c
Explanation:
If a schedule S can be transformed into a schedule S’ by a series of swaps of
non-conflicting instructions, then S and S’ are conflict equivalent. Not all
serial schedules are conflict equivalent to each other.
3. A schedule is __________ if it is conflict
equivalent to a serial schedule.
a) Conflict serializable
b) Conflicting
c) Non serializable
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
A schedule is conflict serializable if it is conflict equivalent to a serial
schedule. The concept of conflict equivalence leads to the concept.
4. The set of ________ in a precedence graph
consists of all the transactions participating in the schedule
a) Vertices
b) Edges
c) Directions
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
The set of vertices in a precedence graph consists of all the transactions
participating in the schedule. Precedence graph is a simple and efficient way
of determining conflict serializability of the schedule.
-------------------------------------------------------------------------
5. A ___________of the transactions can be
obtained by finding a linear order consistent with the partial order of the
precedence graph.
a) Serializability order
b) Direction graph
c) Precedence graph
d) Scheduling scheme
View
Answer
Answer:
a
Explanation:
A Serializability order of the transactions can be obtained by finding a linear
order consistent with the partial order of the precedence graph. This process
is called as topological sorting.
6. State true or false: If I = read(Q) and J =
read(Q) then the order of I and J does not matter.
a) True
b) False
View
Answer
Answer:
a
Explanation:
If I = read(Q) and J = read(Q) then the order of I and J does not matter
because both I and J are read operations on the query.
State true or false: Information residing
in the volatile storage does not usually survive system crashes
a) True
b) False
View Answer
Answer: a
7. State true or false: If I = read(Q) and J =
write(Q) then the order of I and J does not matter.
a) True
b) False
View
Answer
Answer:
b
Explanation:
If I = read(Q) and J = write(Q) then the order of I and J matters because both
I and J are different operations on the query. The order of execution
determines the state of the database that is being read or written.
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1. If a transaction has obtained a __________
lock, it can read but cannot write on the item
a) Shared mode
b) Exclusive mode
c) Read only mode
d) Write only mode
View
Answer
Answer:
a
Explanation:
If a transaction Ti has obtained a shared-mode lock (denoted by S) on item Q,
then Ti can read, but cannot write, Q.
2. If a transaction has obtained a ________
lock, it can both read and write on the item
a) Shared mode
b) Exclusive mode
c) Read only mode
d) Write only mode
View
Answer
Answer:
b
Explanation:
If a transaction has obtained an exclusive mode lock, then it can both read and
write on the item on which it in operating.
3. A transaction can proceed only after the
concurrency control manager ________ the lock to the transaction
a) Grants
b) Requests
c) Allocates
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
A transaction can proceed only after the concurrency control manager grants the
lock to the transaction.
4. If a transaction can be granted a lock on
an item immediately in spite of the presence of another mode, then the two
modes are said to be ________
a) Concurrent
b) Equivalent
c) Compatible
d) Executable
View
Answer
Answer:
c
Explanation:
If a transaction can be granted a lock on an item immediately in spite of the
presence of another mode, then the two modes are said to be compatible.
7. The situation where no transaction can
proceed with normal execution is known as ________
a) Road block
b) Deadlock
c) Execution halt
d) Abortion
View
Answer
Answer:
b
Explanation:
The situation where no transaction can proceed with normal execution is known
as a deadlock.
10. The two phase locking protocol consists which
of the following phases?
a) Growing phase
b) Shrinking phase
c) both a,b
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
The two phased locking protocol consists of the growing phase and the shrinking
phase.
1.
2. Which of the following is not a method in
deadlock handling
a) Deadlock prevention
b) Deadlock detection
c) Deadlock recovery
d) Deadlock distribution
View
Answer
Answer:
d
Explanation:
Deadlock distribution is not a method in deadlock handling whereas, deadlock
prevention is followed by deadlock detection and deadlock recovery.
3. Deadlocks can be prevented using
a) Preemption and transaction rollbacks
b) Wait and die scheme
c) Wound-wait scheme
d) All of the mentioned
View
Answer
Answer:
d
Explanation:
Preemption and transaction rollbacks, wait and die scheme, wound wait scheme
are all different methods of deadlock prevention.
4. State true or false: Wait die scheme is a
non-preemptive technique
a) True
b) False
View
Answer
Answer:
a
Explanation:
The wait-die scheme is a non-preemptive technique. When transaction Ti requests
a data item currently held by Tj , Ti is allowed to wait only if it has a timestamp
smaller than that of Tj (that is, Ti is older than Tj ). Otherwise, Ti is
rolled back (dies).
5.
6. The _________ graph describes deadlocks
precisely
a) Wound wait graph
b) Wait die graph
c) Wait for graph
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
The wait for graph describes deadlocks precisely. Existence of a cycle in this
graph implies that a deadlock will occur.
7. How do we generally recover from a
deadlock?
a) By aborting all the transactions
b) By rolling back all the transactions
c) By rolling back only a selected number of
transactions
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
We generally recover from deadlocks by rolling back only a selected number of
transactions
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8. State true or false: Partial rollback is
not possible.
a) True
b) False
View
Answer
Answer:
b
Explanation:
Partial rollback is possible but it requires the system too maintain an
additional amount of information on the states of the transactions.
9. Which of the following steps must be taken
while choosing a victim?
a) Avoiding starvation
b) Number of transactions involved in rollback
c) Data items used by the transaction
d) All of the mentioned
View
Answer
Answer:
d
Explanation:
While choosing a victim we much choose the one with a minimum cost. That is the
one which avoids starvation, the one with the least number of transaction
involved in the rollback and the one with the least amount of data items used.
7.
9. In timestamp ordering protocol, suppose
that the transaction Ti issues read(Q) and TS(Ti)<W-timestamp(Q), then
a) Read operation is executed
b) Read operation is rejected
c) Write operation is executed
d) Write operation is rejected
View
Answer
Answer:
b
1. The _________ requires each transaction
executes in two or three different phases in its lifetime
a) Validation protocol
b) Timestamp protocol
c) Deadlock protocol
d) View protocol
View
Answer
Answer:
a
Explanation:
The validation protocol requires each transaction to execute in two or three
different phases in its lifetime depending on whether it is a read only or an
update transaction.
2. During __________ phase, the system reads
data and stores them in variables local to the transaction.
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
During the read phase, the system reads data and stores them in variables local
to the transaction. It performs all write operations on temporary local
variables without updates on the actual database.
3. During the _________ phase the validation
test is applied to the transaction
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View
Answer
Answer:
b
Explanation:
During the validation phase, the validation test is applied to the transaction.
This determines whether the transaction is allowed to proceed or not without
causing a violation of serializability.
4. During the _______ phase, the local variables
that hold the write operations are copied to the database
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
During the write phase, the local variables that hold the write operations are
copied to the database. Read only operations omit this phase.
1) Which of
the following is not a recovery technique?
A. Deferred
update
B. Immediate
update
C. Two-phase
commit
D. Recovery
management
2)Checkpoints
are a part of
A. Recovery measures
B. Security measures
C. Concurrency measures
D. Authorization measures
3) .......
deals with soft errors, such as power failures.
A. system
recovery
B. media
recovery
C. database
recovery
D. failure
recovery
4)
........... is an essential part of any backup system.
A. Filter
B. Recovery
C. Security
D.
Scalability
5) Media
recovery deals with ...........
A. disk
errors
B. hard
errors
C. system
errors
D. power
failures
6) For a
backup/restore system, ............. is a prerequisite for service in a
enterprise.
A. Filter
B. Recovery
C. Security
D.
Scalability
7) Failure
recovery and media recovery fall under ........
A.
transaction recovery
B. database
recovery
C. system
recovery
D. value
recovery
9) In which
the database can be restored up to the last consistent state after the system
failure?
A. Backup
B. Recovery
C. Both
D. None
11) In log
based recovery, the log is sequence of .........
A. filter
B. records
C. blocks
E. numbers
13)
.......... is an alternative of log based recovery.
A. Disk
recovery
B. Shadow
paging
C. Dish
shadowing
D. Crash
recovery
-------------------------------------------------------------------------------------------------------------------
10) A
........... is a block of Recovery Manager(RMAN)job commands that is stored in
the recovery catalogue.
A. recovery
procedure
B. recovery
block
C. stored
block
D. stored
script
12) The
enrolling of a database in a recovery catalogue is called .........
A. set up
B. registration
C. start up
D. enrolment
14) Most
backup and recovery commands in ........... are executed by server sessions.
A. Backup
Manager
B. Recovery
Manager
C. Backup
and Recovery Manager
D. Database
Manager
15) ........
systems typically allows to replace failed disks without stopping access to the
system.
A. RAM
B. RMAN
C. RAD
D. RAID
16) An
......... is an exact copy of a single datafile, archived redo log file, or
control file.
A. image
copy
B. datafile
copy
C. copy log
D. control
copy
17)
.......... known as memory-style error correcting-code(ECC) organization,
employs parity bits.
A. RAID
level 1
B. RAID
level 2
C. RAID
level 3
D. RAID
level 4
18) The
remote backup site is sometimes called the .......... site.
A. primary
B. secondary
C. ternary
D. None of
the above
19) EXP
command is used ...........
A. to take
Backup of the Oracle Database
B. to import
data from the exported dump file
C. to create
Rollback segments
D. to create
Schedule.
20) The
simplest approach to introducing redundancy is to duplicate every disk is
called .....
A. mirroring
B. imaging
C. copying
D. All of
the above
Answers:
1) C.
Two-phase commit
2) A.
Recovery measures
3) D.
failure recovery
4) C.
Security
5) A. disk
errors
6) D.
Scalability
7) C. system
recovery
8) A.
Recovery Manager environment
9) B.
Recovery
10) D.
stored script
11) B.
records
12) B.
registration
13) B.
Shadow paging
14) B.
Recovery Manager
15) D. RAID
16) A. image
copy
17) B. RAID
level 2
18) B.
secondary
19) A. to
take Backup of the Oracle Database
20) A.
mirroring
5. A transaction is made to wait until all
________ locks held on the item are released
a) Compatible
b) Incompatible
c) Concurrent
d) Equivalent
View
Answer
Answer:
a
Explanation:
A transaction is made to wait until all compatible locks held on the item are
released. This ensures that no other transaction is concurrently accessing the
same item.
6. State true or false: It is not necessarily
desirable for a transaction to unlock a data item immediately after its final
access
a) True
b) False
View
Answer
Answer:
a
Explanation:
It is not necessarily desirable for a transaction to unlock a data item
immediately after its final access because serializability may be violated due
to this.
8. The protocol that indicates when a
transaction may lock and unlock each of the data items is called as __________
a) Locking protocol
b) Unlocking protocol
c) Granting protocol
d) Conflict protocol
View
Answer
Answer:
a
Explanation:
The protocol that indicates when a transaction may lock and unlock each of the
data items is called as locking protocol. Locking protocols restrict the number
of schedules.
9. If a transaction Ti may never make
progress, then the transaction is said to be ____________
a) Deadlocked
b) Starved
c) Committed
d) Rolled back
View
Answer
A
system is in a _______ state if there exists a set of transactions in which
every transaction is waiting for another transaction in the set.
a) Deadlock
b) Starved
c) Isolated
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
A system is in a deadlock state if there exists a set of transactions in which
every transaction is waiting for another transaction in the set.
Lock
timeouts have which of the following advantages?
a) Unnecessary rollbacks do not occur
b) Transactions do not starve
c) It is easy to implement
d) All of the mentioned
View
Answer
Answer:
d
Explanation:
In lock timeout method, unnecessary rollbacks do not occur, transactions do not
starve and it is also easy to implement and is hence widely used if
transactions are short and long waits are likely to be due to deadlocks.
State true or false: The Thomas write
rule has a greater potential concurrency than the timestamp ordering protocol
a) True
b) False
View
Answer
Answer:
a
Explanation:
The Thomas write rule has a greater potential concurrency than the timestamp
ordering protocol. This is because it is a modified version of the timestamp
ordering protocol in which obsolete write operations can be ignored under certain
circumstances.
8. Which of the following timestamp based
protocols generates serializable schedules?
a) Thomas write rule
b) Timestamp ordering protocol
c) Validation protocol
d) None of the mentioned
View
Answer
Answer:
a
Explanation:
Thomas write rule protocol generates serializable schedules that no other
protocol can generate.
Explanation:
Suppose that transaction Ti issues read(Q). If TS(Ti ) < W-timestamp(Q),
then Ti needs to read a value of Q that was already overwritten. Hence, the
read operation is rejected, and Ti is rolled back.
10. In timestamp ordering protocol, suppose that
the transaction Ti issues write(Q) and TS(Ti)<W-timestamp(Q), then
a) Read operation is executed
b) Read operation is rejected
c) Write operation is executed
d) Write operation is rejected
View
Answer
Answer:
d
Explanation:
In timestamp ordering protocol, suppose that the transaction Ti issues write(Q)
and TS(Ti)<W-timestamp(Q), then the value of Q that Ti is producing was
needed previously, and the system assumed that the value would never be
produced. Hence the system rejects the write(Q) operation and t
5. Read only operations omit the _______ phase
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View
Answer
Answer:
c
Explanation:
Read only operations do not allow write operation to be performed on them. So,
they omit the write phase but execute the read and validation phases.
6. Which of the following timestamp is used to
record the time at which the transaction started execution?
a) Start(i)
b) Validation(i)
c) Finish(i)
d) Write(i)
View
Answer
Answer:
a
Explanation:
There are three different timestamps for each transaction start(i),
validation(i), finish(i). Start(i) is used to record the time at which the
transaction execution started.
8) The
.......... consists of the various applications and database that play a role
in a backup and recovery strategy.
A. Recovery
Manager environment
B. Recovery
Manager suit
C. Recovery
Manager file
D. Recovery
Manager database
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