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DatabaseSystem-SSD7Spring,2012TanChang-gengSchoolofSoftware,CentralSouthUniversityTCG-CSU1.2DatabaseSystemsReferencesCMUSS

D7E-resourceDatabasesystemconcepts(5thed.)bySilberschatz,Korth,Sudarshan,2005,HigherEducationPress.ISBN7-04-019245-4数据库系统概念（上

书中译本），原著：Silberschatz，杨冬青译，机械工业出版社,ISBN7-111-19687-2DatabaseSystems–ApracticalApproachtoDesign,Implementation,andManagement(ThomasConnolly,C

arolynBegg,PersonEducationInc.),ISBN7-5053-8784-7Instructor:TanChanggeng.Email:cgtan163QQ:327414529Offerin

gWorld-LeadingCurriculuminComputerProgramming&SoftwareSystemsDevelopment(SSD)TCG-CSU1.4DatabaseSystemsTwoCertificatesCertificateinCom

puterProgrammingCourses1through5CertificateinSoftwareSystemsDevelopmentCourses1through10SSDCurriculumOverviewTCG-CSU1.5DatabaseS

ystemsiCarnegieCurriculum1-5=CertificateinComputerProgramming1-10=CertificateinSoftwareSystemsDevelopment1:IntroductiontoInformat

ionSystems2:IntroductiontoComputerSystems3:ObjectOrientedProgrammingandDesign5:DataStructuresandAlgorithms6:SystemLevelProgramming10:SoftwarePr

ojectOrganizationandManagement9:SoftwareSpecification,TestandMaintenance8:NetworksandDistributedComputing4:UserCenteredDesignandTesting7:Datab

aseSystemsTCG-CSU1.6DatabaseSystemsWhatdoesiCarnegiedo?10CourseSequenceRootedintheexpertiseofCarnegieMell

onUniversity‘sSchoolofComputerScienceApplied,industry-orientedskillsSoftwareDevelopmentDisciplineSoftwareDevelopment!=ComputerScience

CStrainsscientists/researchersFocusonTheoryHigherMathematicsSoftwareDevelopersarenotresearchersApplied,industryorientedskillsF

ocusonfoundationalskillsTCG-CSU1.7DatabaseSystemsThepurposeofSSD7isforstudentstoBecomefamiliarwithfundamentalDBMSconceptsandwhatadatabasesystemis

LearntouseSQL(structuredquerylanguage)LearntodesigndatabasesystemsLearntodesignandmanagetransaction(事务)LearntoimprovequeryperformanceGa

inexposuretofuturetrendsindatabasesTCG-CSU1.8DatabaseSystemsStudentssuccessfullycompletingSSD7willbeabletoPRODUCE(cont

’d)DatabasedesignsthatsupportagivenapplicationDatamodelsusingE-RdiagramsSoundschemadesignsusingnormalization（使用规范化方法设计出合理的模式）Web-based

databaseapplicationsusingSQLandJSP/ServletsTCG-CSU1.9DatabaseSystemsStudentssuccessfullycompletingSSD7willbeabletoUSE

IndexstructuresofaDBMStoimproveperformanceThetransactionfeaturesofaDBMStoachievefaultrecovery(故障恢复)andconcurrencycontrol(并发控制)Keyrelational

operationstomanipulatedata(操纵数据)SQLDDLtomodeldata,constraints,andviews(视图)SQLDMLtowritecomplexqueriesT

CG-CSU1.10DatabaseSystemsStudentswillbeabletoknowledgeablyDISCUSSThebasicconceptsofobject-relationalandobject-orienteddatabasem

anagementsystemsThebasicconceptsandapplicationofdatawarehousinganddatamining(datacubes,OLAP)Thebasicfunctionsandapplicationofmultimediadata

basesThebasicissuesofdatabaseprivacyandsecurityTheDBMSofferingsofthemostimportantvendorsTCG-CSU1.11DatabaseSystemsDatabaseProgDistributedSysOSUIDat

aStruct&Algorithms数据库的地位TCG-CSU1.12DatabaseSystemsTopicsShallbeLearnedIntroductionRelationalModelS

QLEntity-RelationshipModelRelational-DatabaseDesignTransactionsConcurrencyControlRecoverySystem（Integrity

andSecurity）DatabaseSystemArchitectures……TCG-CSU1.13DatabaseSystemsChapter1:IntroductionPurposeofDatabaseSyst

emsViewofDataDatabaseLanguagesRelationalDatabasesDatabaseDesignObject-basedandsemistructureddatabasesDataStorageandQueryingTransactio

nManagementDatabaseArchitectureDatabaseUsersandAdministratorsOverallStructureHistoryofDatabaseSystemsTCG-CSU1.14DatabaseSyste

ms1.1DatabaseManagementSystem(DBMS)DBMScontainsinformationaboutaparticularenterpriseCollectionofinterrelateddataSetofpro

gramstoaccessthedataAnenvironmentthatisbothconvenientandefficienttouseDatabaseApplications?Banking:alltransactionsAirlines:

reservations,schedulesUniversities:registration,gradesSales:customers,products,purchasesOnlineretailers:ordertracking

,customizedrecommendationsManufacturing:production,inventory,orders,supplychainHumanresources:employeereco

rds,salaries,taxdeductionsDatabasestouchallaspectsofourlivesTCG-CSU1.15DatabaseSystemsTheExamplesofDatabase

SystemsPurchasesusingyourcreditcard信用卡AcreditcarddatabaseThecheckoutassistantAcreditcardreaderCheckyourcreditAddthepu

rchasestodatabaseMonthlystatementstoeachcardholderTCG-CSU1.16DatabaseSystems1.2PurposeofDatabaseSystemsIntheearlydays,da

tabaseapplicationswerebuiltdirectlyontopoffilesystemsDrawbacksofusingfilesystemstostoredata?TCG-CSU1.17DatabaseSystems

LimitationsoftheFile-BasedApproachDataredundancyandinconsistency数据冗余与非一致性Multiplefileformats,duplicationofinformationindiff

erentfiles文件格式不相容，数据冗余Program-datadependence程序依赖于数据NeedtowriteanewprogramtocarryouteachnewtaskDataisolation—mul

tiplefilesandformats数据孤立；文件格式不相容Integrityproblems完整性问题Integrityconstraints(e.g.accountbalance>0)become―buried‖inprogramcoderatherthanb

eingstatedexplicitlyHardtoaddnewconstraintsorchangeexistingonesTraditionalFile-BasedSystems文件系统TCG-CSU1.18DatabaseSystemsDrawbacksofus

ingfilesystems(cont.)Atomicityofupdates原子更新Failuresmayleavedatabaseinaninconsistentstatewithpartialupdatescarri

edoutExample:TransferoffundsfromoneaccounttoanothershouldeithercompleteornothappenatallConcurrentaccessbym

ultipleusers并发访问ConcurrentaccessedneededforperformanceUncontrolledconcurrentaccessescanleadtoinconsistencie

s–Example:Twopeoplereadingabalanceandupdatingitatthesametime(sellticket)SecurityproblemsHardtoprovideuseraccess

tosome,butnotall,dataDatabasesystemsoffersolutionstoalltheaboveproblemsTCG-CSU1.19DatabaseSystemsCharacteristicsoft

heDatabaseApproach数据库方法Data:dataarerawfactsthatdescribepeople,objects,andeventsDatabase:Anintegratedcollectionofrelatedd

ataconstitutesaDatabase(DB).相关数据集成relateddata,thedatarepresentslogicallycoherentfactsaboutsomeaspectsoftherealworldthatarerequiredbyanapplic

ation.Integrated,thedataformultipleapplicationsisstoredtogetherandmanipulatedinauniformwayonasecondarystoragesuchasamagneticor

anopticaldisk.TCG-CSU1.20DatabaseSystemsDatabaseManagementSystemsADatabaseManagementSystem(DBMS)isacollectionofprogramst

hatcontrolsadatabase.General-purposesoftwaresystemDataDefinitionLanguage(DDL)DataManipulationLanguage(DML)Contro

lledaccesstothedatabaseasecuritysystem(authorizedusers)安全性anintegritysystem(consistencyofstoreddata)完整性aconcurrencycontrolsystem(shareda

ccess)并发控制arecoverycontrolsystem(whenH/Sfailure)恢复auser-accessiblecatalog(descriptionsofdata)数据字典TCG-CSU1.21DatabaseSystems

DatabaseSystemaDatabaseSystemconsistsofanapplicationspecificdatabase数据库theDBMSthatmaintainsthatdatabaseDBMStheapplications

oftwarethatmanipulatesthedatabase应用程序数据库系统的个体含义是指一个具体的数据库管理系统软件和用它建立起来的数据库；它的学科含义是指研究、开发、建立、维护和应用数据库系统所涉及的理论、方法、技术所构成的学科。在这一含义下，数据

库系统是软件研究领域的一个重要分支，常称为数据库领域。TCG-CSU1.22DatabaseSystemsTCG-CSU1.23DatabaseSystemsCharacteristicsoftheDatabaseApproachDBMSsembodyt

hethreedistinguishingcharacteristicsofthedatabaseapproach:dataabstraction,reliability,andefficiency.数据抽象可靠性高效TCG-CSU1.24DatabaseSystemsCharacte

risticsoftheDatabaseApproach2DataAbstractionprovideuserswithhigh-level,conceptualrepresentationsofthedata—atableinrelationalDBMSs提供高层、概念的数据表示hides

toragedetailsthatarenotofinteresttomostdatabaseusers隐藏存储细节program-dataindependence数据独立性TCG-CSU1.25DatabaseSy

stemsCharacteristicsoftheDatabaseApproach3Reliability.DBMSsprovidehighreliabilityEnforcingintegrit

yconstraints完整性约束Integrityconstraintsreflectthemeaning(or,thesemantics)ofthedataandoftheapplicationEnsuringdataconsistencydespitehardwareorsoftwar

efailures.数据一致性TansactionsWithinanapplicationprogram,oneormorequery-and-updaterequeststotheDBMScanbelogicallygroupedtogetherinord

ertoperformatask.Agroupofsuchrequestsiscalledatransaction.事务Examples:acustomerpayswithacreditcard,withdrawmoneyfromATMTCG-CSU1.26DatabaseSystems

CharacteristicsoftheDatabaseApproach4Efficiency：DBMSssupportbothefficientspaceutilizationandefficientaccesstodata.

Storingeachdataitemonlyonce减少冗余Enhancingtheperformanceofqueriesbymeansofoptimizationsandtheuseofacces

smethodstodatabasedontheirvalues查询优化Decreasingresponsetimeoftransactionsbyallowingmultipleuserstoaccessthedatabasec

oncurrently并发提高效率TCG-CSU1.27DatabaseSystemsContrastingDatabaseandFileSystemsTCG-CSU1.28DatabaseSystemsFile1File

2FilenProg1Prog2PrognFileSystemTCG-CSU1.29DatabaseSystemsDatabaseProg1Prog2PrognDBMSTCG-CSU1.30DatabaseSystems人工管理文件系统数据库系统应用背景科学

计算科学计算、管理大规模管理硬件背景无直接存取存储设备磁盘、磁鼓大容量磁盘软件背景没有操作系统有文件系统有数据库管理系统背景处理方式批处理联机实时处理批处理联机实时处理,分布处理批处理数据的管理者人文件系统数据库管理系统数据面向的对象某一应用程序某一应用程序整个应用

系统数据的共享程度无共享,冗余度极大共享性差,冗余度大共享性高，冗余度小数据的独立性不独立，完全依赖于程序独立性差具有高度的物理独立性和逻辑独立性数据的结构化无结构记录内有结构，整体无结构整体结构化，用数据模型描述特点数据控制能力应用程序自己控制应用程序自己

控制由数据库管理系统提供数据安全性、完整性、并发控制和恢复能力Comparethedifferentphasesofdatamanagement(Table1)TCG-CSU1.31DatabaseSystemsWhenIsaDatabaseManagementSystemNeede

d?Advantages1ControlofdataredundancyDataconsistencyMoreinformationfromthesameamountofdataSharingofdataImproveddataintegrityImprovedsecurity

EnforcementofstandardsEconomyofscaleTCG-CSU1.32DatabaseSystemsAdvantages2Balanceofconflictingrequireme

ntsImproveddataaccessibilityandresponsivenessIncreasedproductivityImprovedmaintenancethroughdataindependenceIncreas

edconcurrencyImprovedbackupandrecoveryservicesTCG-CSU1.33DatabaseSystemsDisadvantagesComplexitySizeCostofDBMSsAdditionalhardwarec

ostsCostofconversionPerformanceHigherimpactofafailureTCG-CSU1.34DatabaseSystemsWhenIsaDatabaseManagementSystemNotNeeded?Thedatahasasimp

lestructureanditssizeissmall.Theapplication,althoughsimpleandunchanging,hasaspecialpurpose.Concurrentaccesstodata

bymultipleusersisnotrequired.TCG-CSU1.35DatabaseSystemsFourConceptsDataDatabaseDBMS(DatabaseManagementSystems)DB

S(DatabaseSystems)TCG-CSU1.36DatabaseSystemsDatabaseSystemsConceptsData(数据):Dataarerawfactsthatdescribepe

ople,objects,andevents.Or数据实际上就是描述事物的符号记录。例如：文字、图形、图象、声音、学生的档案记录等。数据的形式本身并不能完全表达其内容，需要经过语义解释。数据与其语义是不可分的。Informatio

n(信息):一般把信息理解为关于现实世界事物存在方式或运动状态的反映.TCG-CSU1.37DatabaseSystemsDifferencebetweenDataandInformation数据是信息的符号表示

或称为载体;信息则是数据的内涵，是对数据语义的解释；数据表示了信息，而信息只有通过数据形式才能被计算机理解和接受。TCG-CSU1.38DatabaseSystemsDatabaseAninteg

ratedcollectionofrelateddataconstitutesaDatabase(DB).KeepdatalongtimeLargequantitiesofdataLogicallyr

elatedStructureddataShareTCG-CSU1.39DatabaseSystemsDatabaseManagementSystems(DBMS)ADatabaseManagementSystem(DBMS)isacollectionofprogramsthatcontr

olsadatabase.`Itenablesuserstodefine,create,maintain,andcontrolaccesstothedatabase.Wecanuseitnotonlytocreateandmaintainmultipledatabasesbutalsot

oimplementdatabasesystemsfordifferentapplications.TCG-CSU1.40DatabaseSystemsDatabaseSystemsAdatabasesy

stemisdevelopedtosupporttheoperationsofaspecificorganizationoraspecificsetofapplications.aDatabaseSystemconsistsof1)Anapplicationspecific

database2)TheDBMSthatmaintainsthatdatabase3)TheapplicationsoftwarethatmanipulatesthedatabaseThefigure1-4illustratesasimplif

ieddatabase-systemarchitectureTCG-CSU1.41DatabaseSystemsFigure1-4database-systemarchitectureTCG-CSU1.42DatabaseSystemsRolesintheDa

tabaseEnvironmentDataandDatabaseAdministrators(DAandDBA)DatabaseDesignersLogicalDatabaseDesignersPhysicalDatabaseDe

signersApplicationDevelopersEnd-UsersNaïveusersSophisticatedusersTCG-CSU1.43DatabaseSystems1.3DatabaseArchitectureThearchitectureofadatab

asesystemsisgreatlyinfluencedbytheunderlyingcomputersystemonwhichthedatabaseisrunning:CentralizedClient-server

Parallel(multi-processor)DistributedTCG-CSU1.44DatabaseSystems1.4DatabaseUsersUsersaredifferentiatedb

ythewaytheyexpecttointeractwiththesystemApplicationprogrammers–interactwithsystemthroughDMLcallsSophisticatedusers–formrequestsin

adatabasequerylanguageSpecializedusers–writespecializeddatabaseapplicationsthatdonotfitintothetradit

ionaldataprocessingframeworkNaïveusers–invokeoneofthepermanentapplicationprogramsthathavebeenwrittenpreviouslyExamples,pe

opleaccessingdatabaseovertheweb,banktellers,clericalstaffTCG-CSU1.45DatabaseSystems1.5DatabaseAdministratorCoordinatesalltheactivitiesofthedat

abasesystem;thedatabaseadministratorhasagoodunderstandingoftheenterprise‘sinformationresourcesandneeds.Databaseadministrator'sduti

esinclude:Schemadefinition模式定义StoragestructureandaccessmethoddefinitionSchemaandphysicalorganizat

ionmodificationGrantinguserauthoritytoaccessthedatabaseSpecifyingintegrityconstraintsActingasliaisonwithusersMonitoringperformanceandrespond

ingtochangesinrequirementsTCG-CSU1.46DatabaseSystemsOverallSystemStructureTCG-CSU1.47DatabaseSystems1.6Three-LevelArchitectureDBAshouldbeablet

ochangedatabasestoragestructureswithoutaffectingtheusers’views.Internalstructureofdatabaseshouldbeunaffectedbychanges

tophysicalaspectsofstorage.DBAshouldbeabletochangeconceptualstructureofdatabasewithoutaffectingallusers.Objectives:TCG-CSU1.48Datab

aseSystemsANSI-SPARCThree-LevelArchitectureTCG-CSU1.49DatabaseSystemsANSI-SPARCThree-LevelArchitectureExternalLevel

外部层Users’viewofthedatabase.用户视图Describesthatpartofdatabasethatisrelevanttoaparticularuser.ConceptualLevel概念层Communityviewoft

hedatabase.总体视图Describeswhatdataisstoredindatabaseandrelationshipsamongthedata.InternalLevel内部层Physicalrepresentation

ofthedatabaseonthecomputer.Describeshowthedataisstoredinthedatabase.TCG-CSU1.50DatabaseSystemsDifferencesbetweenThreeLevelsofANSI-SPARC

ArchitectureTCG-CSU1.51DatabaseSystems1.6.1DataIndependence数据依赖LogicalDataIndependenceReferstoimmu

nityofexternalschemastochangesinconceptualschema.概念模式变化不会影响外模式Conceptualschemachanges(e.g.addition/removalofentities).Shouldno

trequirechangestoexternalschemaorrewritesofapplicationprograms.PhysicalDataIndependenceReferstoimmunityofconceptualschematoch

angesintheinternalschema.Internalschemachanges(e.g.usingdifferentfileorganizations,storagestructures/devices).S

houldnotrequirechangetoconceptualorexternalschemas.TCG-CSU1.52DatabaseSystemsDataIndependenceandtheANSI-SPARCTh

ree-LevelArchitectureTCG-CSU1.53DatabaseSystemsViewofDataAnarchitectureforadatabasesystemTCG-CSU1.54DatabaseSystems现

实世界Conceptualmodel转换internalmodelabstractView1View2abstractFigure1-5threedatamodelsTCG-CSU1.55DatabaseSystemsLevelsofAb

stractionPhysicallevel:describeshowarecord(e.g.,customer)isstored.typecustomer=recordcustomer_id:st

ring;customer_name:string;customer_street:string;customer_city:integer;end;Logicallevel:describesdatastoredi

ndatabase,andtherelationshipsamongthedata.Viewlevel:applicationprogramshidedetailsofdatatypes.Viewscanalsohideinformation(suchasanemployee‘ss

alary)forsecuritypurposes.TCG-CSU1.56DatabaseSystemsInstancesandSchemasSimilartovariablesandtypesinprogramminglang

uagesSchema–thelogicalstructureofthedatabaseExample:Thedatabaseconsistsofinformationaboutasetofcustomersandaccountsandther

elationshipbetweenthem)AnalogoustotypeinformationofavariableinaprogramPhysicalschema:databasedesigna

tthephysicallevelLogicalschema:databasedesignatthelogicallevelInstance–theactualcontentofthedatabaseataparticularp

ointintimeAnalogoustothevalueofavariableTCG-CSU1.57DatabaseSystemsInstancesandSchemasPhysicalDataInde

pendence–theabilitytomodifythephysicalschemawithoutchangingthelogicalschemaApplicationsdependonthelogicalschemaIngen

eral,theinterfacesbetweenthevariouslevelsandcomponentsshouldbewelldefinedsothatchangesinsomepartsdonotseriouslyinflue

nceothers.TCG-CSU1.58DatabaseSystems1.7DataModelsAcollectionoftoolsfordescribingDataDatarelationshipsDatasemanticsDataco

nstraints描述数据、数据间联系、数据语义以及约束的概念工具的集合Adatamodelcanbethoughtofascomprisingthreecomponents:数据模型由三部分组成：DatastructureDatamanipulationConstraintsofdata

integrityTCG-CSU1.59DatabaseSystemsDataModelsDataModel:Relationalmodel(Table)Entity-Relationshipdatamodel(m

ainlyfordatabasedesign)Object-baseddatamodels(Object-orientedandObject-relational)Semistructureddatamodel(XML)

Otheroldermodels:NetworkmodelHierarchicalmodelTCG-CSU1.60DatabaseSystems1.8DataManipulationLanguage(DM

L)LanguageforaccessingandmanipulatingthedataorganizedbytheappropriatedatamodelDMLalsoknownasquerylanguageTwoclassesoflanguagesProce

dural过程式–userspecifieswhatdataisrequiredandhowtogetthosedataDeclarative声明式(nonprocedural)–userspecifieswhatdataisrequiredwithoutspecify

inghowtogetthosedataSQListhemostwidelyusedquerylanguageTCG-CSU1.61DatabaseSystemsDataDefinitionLanguage(DDL)Specificationnotationfordefining

thedatabaseschemaExample:createtableaccount(account-numberchar(10),balanceinteger)DDLcompilergeneratesasetoftablesstor

edinadatadictionaryDatadictionarycontainsmetadata(i.e.,dataaboutdata)DatabaseschemaDatastorageanddefinition

languageSpecifiesthestoragestructureandaccessmethodsusedIntegrityconstraintsDomainconstraintsReferentialintegrity(referencesconstraintinSQL

)AssertionsAuthorizationTCG-CSU1.62DatabaseSystemsRelationalModelExampleoftabulardataintherelationalmodelAttributesTCG-CSU1.63DatabaseSystems

ASampleRelationalDatabaseTCG-CSU1.64DatabaseSystems1.9SQLSQL:widelyusednon-procedurallanguageExample:Findthename

ofthecustomerwithcustomer-id192-83-7465selectcustomer.customer_namefromcustomerwherecustomer.customer_id=‗192-83-7465‘Examp

le:Findthebalancesofallaccountsheldbythecustomerwithcustomer-id192-83-7465selectaccount.balancefromdepositor,accountwheredep

ositor.customer_id=‗192-83-7465‘anddepositor.account_number=account.account_numberTCG-CSU1.65DatabaseSystemsApplication

programsgenerallyaccessdatabasesthroughoneofLanguageextensionstoallowembeddedSQLApplicationprograminterface(e.g.,ODBC/JDBC)whichallowSQLque

riestobesenttoadatabaseTCG-CSU1.66DatabaseSystems1.10DatabaseDesignTheprocessofdesigningthegeneralstructureofthedatabase:Logical

Design–Decidingonthedatabaseschema(acollectionofrelationschemas).Databasedesignrequiresthatwefinda“good”collectionofrelationsche

mas.Businessdecision–Whatattributesshouldwerecordinthedatabase?ComputerSciencedecision–Whatrelationschemasshouldwehaveandhowshouldtheattributesbed

istributedamongthevariousrelationschemas?PhysicalDesign–DecidingonthephysicallayoutofthedatabaseTCG-CSU1.67Databas

eSystemsTheEntity-RelationshipModelModelsanenterpriseasacollectionofentitiesandrelationships一单位建模为实体与联系的集合Entity:

a―thing‖or―object‖intheenterprisethatisdistinguishablefromotherobjectsDescribedbyasetofattributesRelationship:anassociationamongseveralentitiesRe

presenteddiagrammaticallybyanentity-relationshipdiagram:TCG-CSU1.68DatabaseSystemsObject-RelationalDataModelsExtendtherelationaldatamodelbyincl

udingobjectorientationandconstructstodealwithaddeddatatypes.Allowattributesoftuplestohavecomplextypes,includingnon-atomicvaluessuchasnestedrelations

.Preserverelationalfoundations,inparticularthedeclarativeaccesstodata,whileextendingmodelingpower.Provideupwardcompatibilitywithexi

stingrelationallanguages.TCG-CSU1.69DatabaseSystemsXML:ExtensibleMarkupLanguageDefinedbytheWWWConsortium(W3C)Originallyintendedasadocumentmarkupl

anguagenotadatabaselanguageTheabilitytospecifynewtags,andtocreatenestedtagstructuresmadeXMLagreatwaytoexchangedata,no

tjustdocumentsXMLhasbecomethebasisforallnewgenerationdatainterchangeformats.Awidevarietyoftoolsisavaila

bleforparsing,browsingandqueryingXMLdocuments/dataTCG-CSU1.70DatabaseSystems1.11StorageManagementStoragemanagerisaprogrammodulethatprovidest

heinterfacebetweenthelow-leveldatastoredinthedatabaseandtheapplicationprogramsandqueriessubmittedtothesystem.Thestoragemanagerisresponsibletothefol

lowingtasks:InteractionwiththefilemanagerEfficientstoring,retrievingandupdatingofdataIssues:StorageaccessFileo

rganizationIndexingandhashingTCG-CSU1.71DatabaseSystems1.12QueryProcessing1.Parsingandtranslation语法分析与转换

2.Optimization优化3.Evaluation评价TCG-CSU1.72DatabaseSystemsQueryProcessing(Cont.)Alternativewaysofevaluatinga

givenqueryEquivalentexpressionsDifferentalgorithmsforeachoperationCostdifferencebetweenagoodandabadwayofev

aluatingaquerycanbeenormousNeedtoestimatethecostofoperationsDependscriticallyonstatisticalinformationaboutrelationswhichthedatabasemus

tmaintainNeedtoestimatestatisticsforintermediateresultstocomputecostofcomplexexpressionsTCG-CSU1.73DatabaseSystems1.12TransactionManagementAtransa

ctionisacollectionofoperationsthatperformsasinglelogicalfunctioninadatabaseapplicationWithinanapplicationprogram,oneormo

requery-and-updaterequeststotheDBMScanbelogicallygroupedtogetherinordertoperformatask.Agroupofsuchrequest

siscalledatransaction.Examples:acustomerpayswithacreditcard,withdrawmoneyfromATMTransaction-managementcomponentensurestha

tthedatabaseremainsinaconsistent(correct)statedespitesystemfailures(e.g.,powerfailuresandoperatingsystemcrashes

)andtransactionfailures.Concurrency-controlmanagercontrolstheinteractionamongtheconcurrenttransactions,toensuret

heconsistencyofthedatabase.TCG-CSU1.74DatabaseSystemsTheDatabaseSystemEnvironmentDatabasesystemiscomposedof5mainparts:1.Hardware2.SoftwareOpera

tingsystemsoftwareDBMSsoftwareApplicationprogramsandutilitysoftware3.People4.Procedures5.DataTCG-CSU1.75DatabaseSystemsTheDa

tabaseSystemEnvironment(continued)TCG-CSU1.76DatabaseSystemsComponentsofaDBMSTCG-CSU1.77DatabaseSystemsCo

mponentsofDatabaseManager(DM)TCG-CSU1.78DatabaseSystemsMulti-UserDBMSArchitecturesTeleprocessingFile-serverClient-serverTCG-CSU1.79Da

tabaseSystemsTeleprocessingTraditionalarchitecture.Singlemainframewithanumberofterminalsattached.Trendisnowtowardsdownsizing.TCG-CSU1.80D

atabaseSystemsTeleprocessingTopologyTCG-CSU1.81DatabaseSystemsFile-ServerFile-serverisconnectedtoseveralworkstationsacrossanetwork.Databa

seresidesonfile-server.DBMSandapplicationsrunoneachworkstation.Disadvantagesinclude:Significantnetworktraffic.CopyofDBMSoneachworkstation.

Concurrency,recoveryandintegritycontrolmorecomplex.TCG-CSU1.82DatabaseSystemsFile-ServerArchitectureTCG-CSU1.83DatabaseSystemsClien

t-ServerServerholdsthedatabaseandtheDBMS.Clientmanagesuserinterfaceandrunsapplications.Advantagesinclude:wideraccesstoexistingdatabases;in

creasedperformance;possiblereductioninhardwarecosts;reductionincommunicationcosts;increasedconsistency.TCG-CSU1.84DatabaseSystems

Client-ServerArchitectureTCG-CSU1.85DatabaseSystemsAlternativeClient-ServerTopologiesTCG-CSU1.86DatabaseSys

temsHistoryofDatabaseSystems1950sandearly1960s:DataprocessingusingmagnetictapesforstorageTapesprovideonlysequentialaccessPu

nchedcardsforinputLate1960sand1970s:HarddisksallowdirectaccesstodataHierarchical(IMS)andNetwork(IDS、DBTG)datamodelsinwidesprea

duse（1G）TedCodddefinestherelationaldatamodelWouldwintheACMTuringAwardforthisworkIBMResearchbeginsSystemRprototypeUCBerkeleybeginsIngre

sprototypeHigh-performance(fortheera)transactionprocessingTCG-CSU1.87DatabaseSystemsHistory(cont.)1980s:Resear

chrelationalprototypesevolveintocommercialsystems（2G）SQLbecomesindustrialstandardParallelanddistributeddatabasesystemsObject-orienteddatabasesyste

ms（3G）1990s:Largedecisionsupportanddata-miningapplicationsLargemulti-terabytedatawarehousesEmergenceof

Webcommerce2000s:XMLandXQuerystandardsAutomateddatabaseadministrationEndofChapter1TCG-CSU1.89DatabaseSystemsFigure1.4TCG-CSU1.90DatabaseSystems

Figure1.7TCG-CSU1.91DatabaseSystemsDatabase(con’t)人们收集并抽取出一个应用所需要的大量数据之后，应将其保存起来以供进一步加工处理，进一步抽取有用信息Def.ofDBAninteg

ratedcollectionofrelateddataconstitutesaDatabase(DB).是长期储存在计算机内、有组织的、可共享的大量数据集合TCG-CSU1.92DatabaseSystems二、数据库(续)数据库的特征数据按一

定的数据模型组织、描述和储存可为各种用户共享冗余度较小数据独立性较高易扩展TCG-CSU1.93DatabaseSystems三、数据库管理系统DBMSAcollectionofprogramsthatcontrolsadatabase.Specifically,

itprovidesuswithaninterfacetocreate,maintain,andmanipulatemultipledatabases.Forgeneral-purpose,是位于用户与操作系统之间的一层数据管理软件。DBMS的用途

科学地组织和存储数据、高效地获取和维护数据TCG-CSU1.94DatabaseSystemsDBMS的主要功能数据定义功能提供数据定义语言(DDL)定义数据库中的数据对象数据操纵功能:提供数据操纵语言(DML)操纵数据实现对数据库的基本操作(查询、插入、删除和修改

)TCG-CSU1.95DatabaseSystemsDBMS的主要功能数据库的运行管理保证数据的安全性、完整性、多用户对数据的并发使用发生故障后的系统恢复数据库的建立和维护功能(实用程序)数据库数据批量装载数据库转储介质故障恢复数据库的重组织性能监视等TCG-CSU1.96Database

Systems四、数据库系统DatabaseSystem:Bedevelopedtosupporttheoperationsofaspecificorganizationoraspecificsetofapplications.Consistsof1

)anapplicationspecificdatabase,2)theDBMSthatmaintainsthatdatabase,and3)theapplicationsoftwarethatmanipulatesthedatabase.(数据库系统（，简称DBS）是指在计算机系统中

引入数据库后的系统构成。在不引起混淆的情况下常常把数据库系统简称为数据库。）数据库系统的构成由数据库、数据库管理系统（及其开发工具）、应用系统、数据库管理员（和用户）构成。TCG-CSU1.97DatabaseSystemsInstruc

tor:谭长庚.(cgtan163)Textbook:Database–systemconcepts(5thed.)bySilberschatz,Korth,Sudarshan,2005Fundamentalsof

DatabaseSystems(4thed.)byElmasri&Navathe,2019Lecturestime:Tue.Am8:00-9:40,15:55-17:30,location:CA-502，CB-402time:Fir.Am8:00-9:40,10:00-11:40loc

ation:CB-402Gradingfinal(70%),others(30%),6(1per2~3weeks)homework1programminghwatmost!