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MCQOPTIONS
This section includes 1294 Mcqs, each offering curated multiple-choice questions to sharpen your Computer Science Engineering (CSE) knowledge and support exam preparation. Choose a topic below to get started.
| 751. |
In crabbing protocol locking |
| A. | goes down the tree and back up |
| B. | goes up the tree and back down |
| C. | goes down the tree and releases |
| D. | goes up the tree and releases |
| Answer» B. goes up the tree and back down | |
| 752. |
How many techniques are available to control concurrency on B+ trees? |
| A. | one |
| B. | three |
| C. | four |
| D. | none of the mentioned |
| Answer» E. | |
| 753. |
Why do we need concurrency control on B+ trees ? |
| A. | to remove the unwanted data |
| B. | to easily add the index elements |
| C. | to maintain accuracy of index |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 754. |
The method of access that uses key transformation is called as |
| A. | direct |
| B. | hash |
| C. | random |
| D. | sequential |
| Answer» C. random | |
| 755. |
Which statement is true regarding synonyms? |
| A. | synonyms can be created for tables but not views |
| B. | synonyms are used to reference only those tables that are owned by another user |
| C. | a public synonym and a private synonym can exist with the same name for the same table |
| D. | the drop synonym statement removes the synonym, and the status of the table on which the synonym has been created becomes invalid |
| Answer» D. the drop synonym statement removes the synonym, and the status of the table on which the synonym has been created becomes invalid | |
| 756. |
A non-correlated subquery can be deï¬ned as |
| A. | a set of sequential queries, all of which must always return a single value |
| B. | a set of sequential queries, all of which must return values from the same table |
| C. | a select statement that can be embedded in a clause of another select statement only |
| D. | a set of one or more sequential queries in which generally the result of the inner query is used as the search value in the outer query |
| Answer» E. | |
| 757. |
Which statements are correct regarding indexes? |
| A. | when a table is dropped, the corresponding indexes are automatically dropped |
| B. | for each dml operation performed, the corresponding indexes are automatically updated |
| C. | a non-deferrable primary key or unique key constraint in a table automatically creates a unique index |
| D. | all of the mentioned |
| Answer» E. | |
| 758. |
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 |
| Answer» E. | |
| 759. |
Lost update problem is |
| A. | second update overwrites the ï¬rst |
| B. | first update overwrites the second |
| C. | the updates are lost due to conflicting problem |
| D. | none of the mentioned |
| Answer» B. first update overwrites the second | |
| 760. |
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 |
| Answer» E. | |
| 761. |
DBMS periodically suspends all processing and synchronizes its ï¬les and journals through the use of |
| A. | checkpoint facility |
| B. | backup facility |
| C. | recovery manager |
| D. | database change log |
| Answer» B. backup facility | |
| 762. |
The extent of the database resource that is included with each lock is called the level of |
| A. | impact |
| B. | granularity |
| C. | management |
| D. | dbms control |
| Answer» C. management | |
| 763. |
A condition that occurs when two transactions wait for each other to unlock data is known as a(n) |
| A. | shared lock |
| B. | exclusive lock |
| C. | binary lock |
| D. | deadlock |
| Answer» E. | |
| 764. |
ANSI-standard SQL allows the use of special operators in conjunction with the WHERE clause. A special operator used to check whether an attribute value is null is |
| A. | between |
| B. | is null |
| C. | like |
| D. | in |
| Answer» C. like | |
| 765. |
The most recent version of standard SQL prescribed by the American National Standards Institute is |
| A. | sql 2016 |
| B. | sql 2002 |
| C. | sql – 4 |
| D. | sql2 |
| Answer» B. sql 2002 | |
| 766. |
A lock that prevents the use of any tables in the database from one transaction while another transaction is being processed is called a |
| A. | database-level lock |
| B. | table-level lock |
| C. | page-level lock |
| D. | row-level lock |
| Answer» B. table-level lock | |
| 767. |
                         denotes the largest timestamp of any transaction that executed write(Q) successfully. |
| A. | w-timestamp(q) |
| B. | r-timestamp(q) |
| C. | rw-timestamp(q) |
| D. | wr-timestamp(q) |
| Answer» B. r-timestamp(q) | |
| 768. |
The                      requires that each transaction Ti executes in two or three different phases in its lifetime, depending on whether it is a read-only or an update transaction. |
| A. | validation protocol |
| B. | validation-based protocol |
| C. | timestamp protocol |
| D. | timestamp-ordering protocol |
| Answer» B. validation-based protocol | |
| 769. |
If a node is locked in                              the subtree rooted by that node is locked explicitly in shared mode, and that explicit locking is being done at a lower level with exclusive-mode locks. |
| A. | intention lock modes |
| B. | shared and intention-exclusive (six) mode |
| C. | intention-exclusive (ix) mode |
| D. | intention-shared (is) mode |
| Answer» C. intention-exclusive (ix) mode | |
| 770. |
If a node is locked in                          then explicit locking is being done at a lower level, with exclusive-mode or shared-mode locks. |
| A. | intention lock modes |
| B. | intention-shared-exclusive mode |
| C. | intention-exclusive (ix) mode |
| D. | intention-shared (is) mode |
| Answer» D. intention-shared (is) mode | |
| 771. |
If a node is locked in                      explicit locking is being done at a lower level of the tree, but with only shared-mode locks. |
| A. | intention lock modes |
| B. | intention-shared-exclusive mode |
| C. | intention-exclusive (ix) mode |
| D. | intention-shared (is) mode |
| Answer» B. intention-shared-exclusive mode | |
| 772. |
If a node is locked in an intention mode, explicit locking is done at a lower level of the tree. This is called |
| A. | intention lock modes |
| B. | explicit lock |
| C. | implicit lock |
| D. | exclusive lock |
| Answer» B. explicit lock | |
| 773. |
                     rollback requires the system to maintain additional information about the state of all the running transactions. |
| A. | total |
| B. | partial |
| C. | time |
| D. | commit |
| Answer» C. time | |
| 774. |
A deadlock exists in the system if and only if the wait-for graph contains a |
| A. | cycle |
| B. | direction |
| C. | bi-direction |
| D. | rotation |
| Answer» B. direction | |
| 775. |
The deadlock in a set of a transaction can be determined by |
| A. | read-only graph |
| B. | wait graph |
| C. | wait-for graph |
| D. | all of the mentioned |
| Answer» B. wait graph | |
| 776. |
The situation where the lock waits only for a speciï¬ed amount of time for another lock to be released is |
| A. | lock timeout |
| B. | wait-wound |
| C. | timeout |
| D. | wait |
| Answer» B. wait-wound | |
| 777. |
When transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp larger than that of Tj (that is, Ti is younger than Tj ). Otherwise, Tj is rolled back (Tj is wounded by Ti). This is |
| A. | wait-die |
| B. | wait-wound |
| C. | wound-wait |
| D. | wait |
| Answer» D. wait | |
| 778. |
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). This is |
| A. | wait-die |
| B. | wait-wound |
| C. | wound-wait |
| D. | wait |
| Answer» B. wait-wound | |
| 779. |
What are the ways of dealing with deadlock? |
| A. | deadlock prevention |
| B. | deadlock recovery |
| C. | deadlock detection |
| D. | all of the mentioned |
| Answer» E. | |
| 780. |
The deadlock state can be changed back to stable state by using                            statement. |
| A. | commit |
| B. | rollback |
| C. | savepoint |
| D. | deadlock |
| Answer» C. savepoint | |
| 781. |
A system is in a              state if there exists a set of transactions such that every transaction in the set is waiting for another transaction in the set. |
| A. | idle |
| B. | waiting |
| C. | deadlock |
| D. | ready |
| Answer» D. ready | |
| 782. |
Which of the following is a procedure for acquiring the necessary locks for a transaction where all necessary locks are acquired before any are released? |
| A. | record controller |
| B. | exclusive lock |
| C. | authorization rule |
| D. | two phase lock |
| Answer» E. | |
| 783. |
The          lock allows concurrent transactions to access the same row as long as they require the use of different ï¬elds within that row. |
| A. | table-level |
| B. | page-level |
| C. | row-level |
| D. | field-level |
| Answer» E. | |
| 784. |
Which of the following protocols ensures conflict serializability and safety from deadlocks? |
| A. | two-phase locking protocol |
| B. | time-stamp ordering protocol |
| C. | graph based protocol |
| D. | none of the mentioned |
| Answer» C. graph based protocol | |
| 785. |
Which of the following are introduced to reduce the overheads caused by the log- based recovery? |
| A. | checkpoints |
| B. | indices |
| C. | deadlocks |
| D. | locks |
| Answer» B. indices | |
| 786. |
Which refers to a property of computer to run several operation simultaneously and possible as computers await response of each other |
| A. | concurrency |
| B. | deadlock |
| C. | backup |
| D. | recovery |
| Answer» B. deadlock | |
| 787. |
A lock that allows concurrent transactions to access different rows of the same table is known as a |
| A. | database-level lock |
| B. | table-level lock |
| C. | page-level lock |
| D. | row-level lock |
| Answer» E. | |
| 788. |
Which of the following is the original purpose of SQL? |
| A. | to specify the syntax and semantics of sql data deï¬nition language |
| B. | to specify the syntax and semantics of sql manipulation language |
| C. | to deï¬ne the data structures |
| D. | all of the mentioned |
| Answer» E. | |
| 789. |
SQL can be used to: |
| A. | create database structures only |
| B. | query database data only |
| C. | modify database data only |
| D. | all of the mentioned |
| Answer» E. | |
| 790. |
Which of the following statements is/are not true for SQL proï¬ler? |
| A. | enables you to monitor events |
| B. | check if rows are being inserted properly |
| C. | check the performance of a stored procedure |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 791. |
Isolation of the transactions is ensured by |
| A. | transaction management |
| B. | application programmer |
| C. | concurrency control |
| D. | recovery management |
| Answer» D. recovery management | |
| 792. |
Which statement is true regarding external tables? |
| A. | the default reject limit for external tables is unlimited |
| B. | the data and metadata for an external table are stored outside the database |
| C. | oracle_loader and oracle_datapump have exactly the same functionality when used with an external table |
| D. | the create table as select statement can be used to unload data into regular table in the database from an external table |
| Answer» E. | |
| 793. |
SNAPSHOT is used for (DBA) |
| A. | synonym |
| B. | tablespace |
| C. | system server |
| D. | dynamic data replication |
| Answer» E. | |
| 794. |
In which scenario would you use the ROLLUP operator for expression or columns within a GROUP BY clause? |
| A. | to ï¬nd the groups forming the subtotal in a row |
| B. | to create group-wise grand totals for the groups speciï¬ed within a group by clause |
| C. | to create a grouping for expressions or columns speciï¬ed 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 speciï¬ed within a group by clause in all possible directions, which is cross- tabular report for calculating the subtotals |
| Answer» D. to create a grouping for expressions or columns speciï¬ed within a group by clause in all possible directions, which is cross- tabular report for calculating the subtotals | |
| 795. |
A concurrency-control policy such as this one leads to              performance since it forces transactions to wait for preceding transactions to ï¬nish before they can start. |
| A. | good |
| B. | average |
| C. | poor |
| D. | unstable |
| Answer» D. unstable | |
| 796. |
In concurrency control policy the lock is obtained on |
| A. | entire database |
| B. | a particular transaction alone |
| C. | all the new elements |
| D. | all of the mentioned |
| Answer» B. a particular transaction alone | |
| 797. |
Which server can join the indexes when only multiple indexes combined can cover the query: |
| A. | sql |
| B. | dbms |
| C. | rdbms |
| D. | all of the mentioned |
| Answer» B. dbms | |
| 798. |
                     are used to ensure that transactions access each data item in order of the transactions’          if their accesses conflict. |
| A. | zone |
| B. | relay |
| C. | line |
| D. | timestamps |
| Answer» E. | |
| 799. |
Which are types of recovery control techniques: |
| A. | deferred update |
| B. | immediate update |
| C. | all of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 800. |
Copying ï¬les to secondary or speciï¬c devices is known as |
| A. | retrieve |
| B. | backup |
| C. | recovery |
| D. | deadlock |
| Answer» C. recovery | |