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