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FIT2094WEEK1Databases
Databasesarespecializedstructuresthatallowcomputer-basedsystemstostore,manageandretrievedataveryquickly.
Dataismanagedmostefficiently,whenstoredinadatabase. Databasesevolvedfromcomputerfilesystems.WhyDatabases?Withinmodernsociety,dataisubiquitous(abundant,global)andpervasive.Databasesmakedatapersistentandshareableinasecureway.Itisessentialfororganizationstoprosper,andtheymusthavethisdataavailabletodecisionmakerswhennecessary.Possibly,theultimatepurposeofbusinessinformationsystemsistohelpbusinessesuseinformationasanorganizationalresource.Intheheartofallofthesesystemsarethecollection,storage,aggregation,manipulation,dissemination,andmanagementofdata.- DatacouldvaryfromafewmegabytesonjustoneortwotopicsORterabytescovering
hundredsoftopics- Telecommunicationscompanies,suchasSprintandAT&T,areknowntohavesystems
thatkeepdataontrillionsofphonecalls,withnewdatabeingaddedtothesystematspeedsupto70,000callspersecond!Notonlydothesecompanieshavetostoreandman-ageimmensecollectionsofdata,theyhavetobeabletoandanygivenfactinthatdataquickly.
DatavsInformationDataconsistsofrawfacts,andhencefactshavenotbeenyetprocessedtorevealtheirmeaning.Rawdatamustbeproperlyformattedforstorage,processingandpresentation.Informationistheresultofprocessingrawdatatorevealitsmeaning.Dataprocessingcanbeassimpleasorganizingdatatorevealpatternsorascomplexasmakingforecasts.- Dataconstitutesthebuildingblocksofinformation.- Informationisproducedbyprocessingdata.- Informationisusedtorevealthemeaningofdata.- Accurate,relevant,andtimelyinformationisthekeytogooddecisionmaking.- Gooddecisionmakingisthekeytoorganizationalsurvivalinaglobalenvironment.
Datamanagementisadisciplinethatfocusesonpropergeneration,storageandretrievalofdataORaprocessthatfocusesondatacollection,storageandretrieval.IntroducingthedatabaseAdatabaseisashared,integratedcomputerstructurethatstoresacollectionofthefollowing:- End-userdata(rawfactsofinteresttotheenduser)- Metadata,ordataaboutdata,throughwhichtheend-userdataisintegratedand
managedMetadatadescribesthedatacharacteristicsandthesetofrelationshipsthatlinksthedatafoundwithinthedatabase.Adatabasemanagementsystem(DBMS)isacollectionofprogramsthatmanagesthedatabasestructureandcontrolsaccesstothedatastoreswithinadatabase.
RolesandAdvantagesoftheDBMSTheDBMSactsastheintermediarybetweentheuserandthedatabase.TheDBMSreceivesallapplicationrequestsandtranslatesthemintothecomplexoperationsrequiredtofufillthoserequests.Ithidesmuchofthedatabase’sinternalcomplexityfromtheapplicationprogramsandusers.AdvantagesoftheDBMS:- ADBMSenablesthedatainthedatabasetobesharedamongmultipleapplicationsof
users.- DBMSintegratesthemanydifferentusers’viewsofthedataintoasingle-all
encompassingdatarepository.- TheDBMSimprovesdatasharing,andhelpscreateanenvironmentinwhichendusers
havebetteraccesstomoreandbettermanageddata- Minimizesdatainconsistency.Datainconsistencyexistswhendifferentversionsofthe
samedataappearsindifferentplaces.- Makesitpossibletoproducequickanswerstoadhocqueries.Aqueryisaquestionor
taskaskedbyanenduserofadatabaseintheformofaSQLcode.TypesofDatabasesADBSMcanbeusedtobuildmanydifferenttypesofdatabases.- EachdatabasestoresaparticularcollectionofdataandisusedforaspecificpurposeBYSIZEAsingleuserdatabase:
SupportsonlyoneuseratatimeAdesktopdatabase: Supportsasingle-userdatabasethatrunsonapersonalcomputerAmultiuserdatabase: AdatabasethatsupportsmultipleconcurrentusersAworkgroupdatabase:
Amultiuserdatabasethatusuallysupportsfewerthan50usersorisusedforaspecificdepartmentinanorganisaiton
Anenterpriseddatabase:Theoverallcompanydatarepresentation,whichprovidessupportforpresentandunexpectedfutureneeds
BYLOCATION,theseneedawell-definedinfrastructuretoimplementandoperatethedatabaseAcentralizeddatabase: AdatabaselocatedatasinglesiteAdistributeddatabase: AlogicallyrelateddatabasethatisstoredintwoormorephysicallyindependentsitesAclouddatabase: AdatabasethatiscreatedandmaintainedusingcloudservicesBYTYPEOFDATAGeneralpurposedatabases ContainawidevarietyofdatausedinmultipledisciplinesDiscipline-specificdatabses ContaindatafocusedonspecificsubjectareasBYHOWTHEYWILLBEUSED(MOSTPOPULAR)Operationaldatabase Adatabasedesignedprimarilytosupportacompany’sdaytodayoperatesAnalyticaldatabase
Adatabasefocusedonstoringhistoricaldataandbusinessmetricsusedfortacticalorstrategicdecisionmakingo Datawarehouse,isthecomponentthatstoreshistoricaldataobtainedfromthe
operationaldatabaseso Onlineanalyticalprocessing(OLAP),isasetoftoolsthatworktogetherto
provideanadvanceddataanalysisenvironmentforretrieving,processingandmodellingdatafromthewarehouse.
BYTHEDEGREETOWHICHTHEDATAISSTRUCTUREDUnstructureddata: Datainitsoriginal(raw)stateStructureddata:
Theresultofformattingunstructureddatatofacilitatestorage,use,andthegenerationofinformation
UnstructuredandsemistructureddatastorageandmanagementneedsarebeingaddressedthroughanewgenerationofdatabasesknownasXML(ExtensibleMarkUpLanguage),torepresentandmanipulatedataelementsinatextualformat.AnXMLdatabasesupportsthestorageandmanagementofasemi-structuredXMLdata
Whydatabasedesignisimportant- Aproblemthathasevolvedwiththeuseofpersonalproductivitytoolssuchas
spreadsheetsanddesktopdatabaseprograms,isthatpeopletypicallylackproperdatabasedesign,
- Furthermore,manycomputer-savvybusinessesgainafalsesenseofconfidenceintheirabilitytobuildafunctionaldatabase
DATABASEDESIGNReferstotheactivitiesthatfocusonthedesignofthedatabasestructurethatwillbeusedtostoreandmanageend-userdata.Awelldesigneddatabasefacilitatesdatamanagementandgeneratesaccurateandvaluableinformation
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