Database Management Systems

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Q & A
1Making a change to the conceptual schema of a database but not affecting the existing external schemas is an example ofPhysical data independenceConcurrency controlLogical data independenceFunctional dependencyC
2Which key word is available in SQL to enforce referential integrity?CheckPrimary KeySet DefaultUniqueB
3Which of the following statements are Data Definition Language commands?INSERTUPDATEGRANTTRUNCATED
4How many clustered index(es) do each database table have?2351D
5Which of the following is true about DELETE command?is DDL CommandResets identity of the tablecannot activate a triggerCan be Rolled backA
6Which of the following will be deleted relating to a table if you use TRUNCATE command?all rows in a tableindexestable structure and its columnsconstraintsA
7Which of the following is not true about De-normalization?It is the process of attempting to optimize the performance of a databaseDe-normalization is a technique to move from lower to higher normal forms of database modelingIn de-normalization it is required to add redundant data.It enhances the performance of DBB
8Which of the following is not a feature of TRANSACTION?Users should be able to regard the execution of each transaction as atomicEach transaction, run by itselfMust preserve the consistency of the databaseDependant on other concurrent transactionsD
9Which of the following gives all the fields from employee table named as EMP?select * from EMP;select emp* from EMP'select emp_id where EMP;select * where EMP;A
10Suppose there are 4 fields in a table named CUST (customer_id, first_name, last_name, phone). Which of the following gives all the information of the customers in the table whose last name is ALI?SELECT * FROM CUST WHERE last_name='ALI';SELECT * FROM CUST WHERE last_name=ALI;SELECT * FROM CUSTOMER WHERE name=ALI;SELECT * FROM CUSTOMER WHERE last_name=ALI;A
11Identify the correct statement with respect to normalization.Normalization is a formal technique that can be used only at the starting phase of the database design.Normalization can be used as a top-down standalone database design technique.The process of normalization through decomposition must achieve the lossless join property at any cost whereas the dependency reservation property is sometimes sacrificed.The process of normalization through decomposition must achieve the dependency reservation property at any cost whereas the lossless join property is sometimes sacrificed.D
12Which of the following is not true with respect to denormalization?A denormalized data model is not the same as a data model that has not been normalizedDenormalization takes place before the normalization processIt is an attempt to optimize the performance of databaseDenormalization process can not be initiated before the Database designC
13Which of the following is incorrect with respect to indexed sequential files?New records are added to an overflow fileRecord in main file that precedes it is updated to contain a pointer to the new recordThe overflow is merged with the main file during a batch updateMultiple indexes for the same key field cannot be setupD
14Which of the following types of partitioning reduces the chances of unbalanced partitions?verticalListHashRangeC
15DML commands are used for:inserting data into databasesCreating databasesDestroying databasesCreating DB objectsA
16Which of the following is correct regarding Dataflow diagram?Single DFD is required to represent a systemCreated at increasing levels of detailThe dataflow must be bidirectionalUsed to represent the relationships among the external entitiesA
17What is the impact of setting multiple indexes for the same key, in index sequential files?Multiple indexes for the same key can not be setIt will increase complexity as the access time will be increasedIt increases efficiencyIt decreases efficiencyC
18Which of the following is not true regarding Indexes?Index can be defined even when there is no data in the tableIt can be created using ‘Create Index’ statementIt support Range selectionsIt can not be created on composite attributesD
19While recovering data, which of the following files does a recovery manager examines at first?A system fileLog fileData dictionaryMetadataB
20The main memory of a computer system is also known asROMRAMPROMHard diskB
21_______is a control that enables users to select one option from an associated list; users can also type an option.Combo boxButtonText boxStatic areaB
22 _______ records data by burning microscopic holes in the surface of the disk with a laser.Hard diskRAMOptical diskFloppy diskC
23Which of following is NOT generally the aim of data partitioning and placement of data?Reduce WorkloadBalance WorkloadMerging different relationsSpeed up rate of useful worksC
24Which feature of database provides conversion from inconsistent state of DB to a consistent state ensuring minimum data loss?User accessible catalogData processingAuthorization serviceRecovery serviceD
25Which of the following statements is true about the views?View is always a complete set of all the tables in a databaseView can not be used for retrieving dataThe results of using a view are not permanently stored in the databaseRows can not be updated or deleted in the viewD