高级数据库系统选择题(附答案)

目录Ordered Indexing and Hashing (1)Buffer Management (3)Bitmap Indices (5)Ordered Indices (7)B+ trees (8)Organization of Records in Files (10)Ordered Indexing and HashingThis set of Database Multiple Choice Questions & Answers (MCQs) focuses on “Ordered Indexing and Hashing”.1. A(n) ___c_____ can be used to preserve the integrity of a document or a message.a) Message digestb) Message summaryc) Encrypted messaged) None of the mentioned2. A hash function must meet ___b____ criteria.a) Twob) Threec) Fourd) None of the mentioned3. What is the main limitation of Hierarchical Databases? ba) Limited capacity (unable to hold much data)b) Limited flexibility in accessing datac) Overhead associated with maintaining indexesd) The performance of the database is poor4. The property (or set of properties) that uniquely defines each row in a table is called the:a) Identifierb) Indexc) Primary keyd) Symmetric key5. The separation of the data definition from the program is known as: ba) Data dictionaryb) Data independencec) Data integrityd) Referential integrity6. In the client / server model, the database: da) Is downloaded to the client upon requestb) Is shared by both the client and serverc) Resides on the client sided) Resides on the server side7. The traditional storage of data that is organized by customer, stored in separate folders in filing cabinets is an example of what type of ‘database’ system? aa) Hierarchicalb) Networkc) Object orientedd) Relational8. The database design that consists of multiple tables that are linked together through matching datastored in each table is called da) Hierarchical databaseb) Network databasec) Object oriented databased) Relational database9. The association role defines: aa) How tables are related in the databaseb) The relationship between the class diagram and the tables in the databasec) The tables that each attribute is containedd) Which attribute is the table’s primary key10. The purpose of an N-Ary association is: ca) To capture a parent-child relationshipb) To deal with one to many relationshipsc) To deal with relationships that involve more than two tablesd) To represent an inheritance relationshipBuffer Management1. In order to reduce the overhead in retrieving the records from the storage space weuse ba) Logsb) Log bufferc) Medieval spaced) Lower records2. The order of log records in the stable storage ______ a ______ as the order in whichthey were written to the log buffer.a) Must be exactly the sameb) Can be differentc) Is opposited) Can be partially same3.Before a block of data in main memory can be output to the database, all log recordspertaining to data in that block must have been output to stable storage. This is (c)a)Read-write loggingb) Read-ahead loggingc) Write-ahead loggingd) None of the mentioned4. Writing the buffered log to ____d______ is sometimes referred to as a log force.a) Memoryb) Backupc) Redo memoryd) Disk5. The ______b________ policy, allows a transaction to commit even if it has modifiedsome blocks that have not yet been written back to disk.a) Forceb) No-forcec) Steald) No-steal6. ______b________ policy allows multiple updates to accumulate on a block before itis output to stable storage, which can reduce the number of output operations greatly for frequently updated blocks.a) Forceb) No-forcec) Steald) No-steal7.The ______c_____ policy, allows the system to write modified blocks to disk even ifthe transactions that made those modifications have not all committed.a) Forceb) No-forcec) Steald) No-steal8.Locks on buffer blocks are unrelated to locks used for concurrency-control oftransactions, and releasing them in a non-two-phase manner does not have any implications on transaction serializability. This is (a)a) Latchesb) Swap Spacec) Dirty Blockd) None of the mentioned9.The _________c_________ contains a list of blocks that have been updated in thedatabase buffer.a) Latchesb) Swap Spacec) Dirty Blockd) None of the mentioned10.The operating system reserves space on disk for storing virtual-memory pages thatare not currently in main memory; this space is called (b)a) Latchesb) Swap Spacec) Dirty Blockd) None of the mentionedBitmap Indices1. Bitmap indices are a specialized type of index designed for easy querying on_____c______a) Bit valuesb) Binary digitsc) Multiple keysd) Single keys2. A ___a____ on the attribute A of relation r consists of one bitmap for each value that Acan take.a) Bitmap indexb) Bitmapc) Indexd) Array3.SELECT *FROM rWHERE gender = ’f’ AND income level = ’L2’;In this selection, we fetch the bitmaps for gender value f and the bitmap for income level value L2, and perform an ___d___ of the two bitmaps.a) Unionb) Additionc) Combinationd) Intersection4.To identify the deleted records we use the _____a________a) Existence bitmapb) Current bitmapc) Final bitmapd) Deleted bitmap5.Bitmaps can be used as a compressed storage mechanism at the leaf nodes of____b____ for those values that occur very frequently.a) B-treesb) B+-treesc) Bit treesd) Both B-trees and B+-trees6.Bitmaps can be combined with regular B+-tree indices for relations where a fewattribute values are extremely common, and other values also occur, but much less frequently. ba) Bitmap, B-treeb) Bitmap, B+treec) B-tree, Bitmapd) B+tree, Bitmap7.In a B+-tree index ___a___ for each value, we would normally maintain a list of allrecords with that value for the indexed attribute.a) Leafb) Nodec) Rootd) Link8. A tablespace is further broken down into ____b____a) Tablespaceb) Segmentsc) Extentsd) Blocks9.In ordered indices the file containing the records is sequentially ordered, a______a_____ is an index whose search key also defines the sequential order of the file.a) Clustered indexb) Structured indexc) Unstructured indexd) Nonclustered index10.Indices whose search key specifies an order different from the sequential order of thefile are called _____c______ indices.a) Nonclusteredb) Secondaryc) All of the mentionedd) None of the mentionedOrdered Indices1. In ordered indices the file containing the records is sequentially ordered, a_____a______ is an index whose search key also defines the sequential order of the file.a) Clustered indexb) Structured indexc) Unstructured indexd) Nonclustered index2.Indices whose search key specifies an order different from the sequential order ofthe file are called _____c______ indices.a) Nonclusteredb) Secondaryc) All of the mentionedd) None of the mentioned3.An _______a_____ consists of a search-key value and pointers to one or morerecords with that value as their search-key value.a) Index entryb) Index hashc) Index clusterd) Index map4.In a ___a____ clustering index, the index record contains the search-key valueand a pointer to the first data record with that search-key value and the rest of the records will be in the sequential pointers.a) Denseb) Sparsec) Straightd) Continuous5.In a ______a____ index, an index entry appears for only some of the search-keyvalues.a) Denseb) Sparsec) Straightd) Continuous6.Incase the indices values are larger, index is created for these values of the index.This is called (c)a) Pointed indexb) Sequential indexc) Multilevel indexd) Multiple index7. A search key containing more than one attribute is referred to as a ___b______search key.a) Simpleb) Compositec) Compoundd) Secondary8.In B+ tree the node which points to another node is called (d)a) Leaf nodeb) External nodec) Final noded) Internal node9.Insertion of a large number of entries at a time into an index is referred to as_______c___ of the index.a) Loadingb) Bulk insertionc) Bulk loadingd) Increase insertion10.While inserting the record into the index, if the search-key value does not appearin the index. (c)a) The system adds a pointer to the new record in the index entryb) The system places the record being inserted after the other records with thesame search-key valuesc) The system inserts an index entry with the search-key value in the index at theappropriate positiond) None of the mentionedB+ trees1. State true or false: B+ trees are not always balanced trees. ba) Trueb) False2.What are the leaf nodes in a B+ tree? ba) The topmost nodesb) The bottommost nodesc) The nodes in between the top and bottom nodesd) None of the mentioned3.Non-leaf nodes are also called as _____a_____a) Internal nodesb) External nodesc) Middle nodesd) Primary nodes4.The queries used to find all records with search key values in a particular range areknown as ___c_____a) Gap queriesb) Graph queriesc) Range queriesd) None of the mentioned5.Statement 1: Insertion of record might require the change in position of the initialnodes.Statement 2: Deletion of records might require the change in position of the initial nodes. (a)a) Both the statements are trueb) Statement 1 is true but statement 2 is falsec) Statement 2 is true but statement 1 is falsed) Both the statements are false6.If a relation can have more than one record containing the same search key value, thesearch key is said to be a ____b______a) Unique search keyb) Non unique search keyc) Multiple search keyd) Identical search key7.State true or false: The fanout of nodes can be increased by using a technique called____a_____a)Prefix compressionb) Postfix compressionc) Prefix expansiond) Postfix expansion8. Insertion of a large number of entries at a time into an index is referred to as ___a____ of the index.a) Bulk loadingb) Mass insertionc) Quick insertiond) Quick loading9._____b______ are the indices that store the values of some attributes along with the pointers to the recor.a) Binary indicesb) Covering indicesc) Key indicesd) Static indicesOrganization of Records in Files1. If a piece of data is stored in two places in the database, thena) Storage space is wastedb) Changing the data in one spot will cause data inconsistencyc) In can be more easily accessedd) Storage space is wasted & Changing the data in one spot will cause data inconsistencyAnswer: dExplanation: The database is always consistent and so there is no duplication.2.An audit trail ___________a) Is used to make backup copiesb) Is the recorded history of operations performed on a filec) Can be used to restore lost informationd) None of the mentionedAnswer: bExplanation: This is more useful for all recovery actions.3. Large collection of files are called ____________a) Fieldsb) Recordsc) Databased) SectorsAnswer: cExplanation: The operator tree has a tree like format where the evaluation starts from root of the tree .4. Which of the following hardware component is the most important to the operation of a database management system?a) High resolution video displayb) Printerc) High speed, large capacity diskd) MouseAnswer: cExplanation: All the data are stored in form of memory in the disk.5. Which of the following is not true of the traditional approach to information processinga) There is common sharing of data among the various applicationsb) It is file orientedc) Programs are dependent on the filed) It is inflexibleAnswer: aExplanation: All the data are stored in form of memory in the disk.6. Which of these is not a feature of Hierarchical model?a) Organizes the data in tree-like structureb) Parent node can have any number of child nodesc) Root node does not have any parentd) Child node can have any number of parent nodesAnswer: dExplanation: The data are traversed using several algorithms.7. Which of these data models is an extension of the relational data model?a) Object-oriented data modelb) Object-relational data modelc) Semi structured data modeld) None of the mentionedAnswer: bExplanation: All the data are stored in form of memory in the disk.8. The information about data in a database is called _______a) Metadatab) Hyper datac) Tera datad) None of the mentionedAnswer: aExplanation: Metadata is information about a data.9. A data dictionary is a special file that contains?a) The names of all fields in all filesb) The data types of all fields in all filesc) The widths of all fields in all filesd) All of the mentionedAnswer: dExplanation: The data dictionary is structured in tables and views, just like other database data.10. The DBMS acts as an interface between what two components of an enterprise-class database system?a) Database application and the databaseb) Data and the databasec) The user and the database applicationd) Database application and SQLAnswer: aExplanation: Database application is the interface with the user to access the database.。