Relational Databases

Essay samples

RelationalDatabases

DatabaseOrientation Paper

RelationalDatabase

Thisis acollectionof data itemsputin orderas a setof formally describedtablesfrom which informationcan be accessedin numerouswayswithout havingto reorganizethedata (Domanski, 2000). Thestandardapplicationanduser programinterface to relational datais theSQL (standardquerylanguage).Data isfittedinto labeledcategories.Thetablesare referredto as relationsandcontainone ormoredata categoriesin files(Sumathi&amp Esakkirajan, 2007). Forinstance,a classicalrelational database fora businessorderentrywould compriseof tablesthat describea clientwith columnsfrom names,cellphonenumberandaddress.An additionaltablewould givedetailsof theorderproducts,sellingprice,customeranddateof sale.In thisexample,theuser of therelationdatabase would be in a positionto viewthedatabase that matchedtheuser’s needs.Afinancialmanagerin thiscompanywould finditeasyto accessandobtaina statementon all theaccountstheneedto bepaid.In thesameway,asupervisorwould be ableto viewandaccessallreportson allclientsthat hadpurchaseda productafter a particulardate.

DataNormalization

Normalizationis theprocessof resourcefully organizingdata in a database. Normallythere are two aimsof normalizing data removalof redundantdata andmakingsurethatdata dependenciesmakesense(Albright,2012). Redundant data may be data that is appearingin morethan one table,in therelationdatabase, whiledata that makessenserefersto data that isrelatedin a table.Normalization reducesthebulkof data that isstoredin thetablesandthuslowers theamountof spacethata database willconsume.Normalization ensuresthatthetablesareusedoptimally and efficiently. Efficiencydoesnot necessarilymeanreductionof data complexity neitherdoesitresultsto betterperformance.Asystematicexaminationis necessaryto identifytheinterrelationship of data storein a giventable.Itresultsto significantimprovementin thespeedin which data can beviewedandcomparedandreducesthepossibilitythatdata could becompromisedas a resultof cumbersome maintenanceprocedures.Italsoaverts duplication of data in thedatabase (Albright,2012). Thegoalof 1NF is to dividethebasedata into logicalunitsreferredto as tables.Theobjectiveof 2NF is to takedata that is partlyrelatedon thebasickeyandenterthedata into a differenttable.Thegoalof the3NF is to takeout data from a tablethat is not dependenton theprimarykey.

NormalForms

CoddtheIBM researcher whoisrecognizedas thecreatorof thenormalformscameup with guidelines to facilitatetheprocessof normalization. Theseguidingprincipleare referredto as normalformsandareenumeratedfrom one (1NF), alsoreferredto as firstnormalformthrough to 2NF, 3NF, 4NF andfive (5NF). Itis worthnotingthatall thenormalformsarenested,thatis, ifa database meets3NF thenitfollowsthatitmeets1NF and2NF (Albright,2012).

LogicalandPhysicalDatabase Design

Physicalandlogicaldatabase designsareneededin ordertovisually presentdatabase thathas beenrecommendedforparticularbusinessrequirements.Bothmodelsassistin depictingtherelationshipbetween thedatabase itemsandbusinessrequirements.Itis importantto representdata in eitherof thisformin orderto gatherall therequirementof thedatabase succinctly andaccurately.Data modeling is thecorrelationbetween thebusinessneedsandthesystemrequirements(Sumathi&amp Esakkirajan, 2007).

LogicalDatabase Model

Logicaldatabase designisneededforgatheringbusinessneedsandpresentingtherequirementsas a model.Itis mostlyconnectedwith thegatheringof businessrequirementsratherthan database design.Informationthat can becollectedcould be about businessentities,processesandunits.Whenthisinformationisassembled,diagramsandreportsare made.Alogicaldatabase preparesthewayforthecreationof physicaldesign.Itis normallyreviewedby managementandotherusers to seewhethermoreinformationneedsto becollectedbefore physicalmodeling (Sumathi&amp Esakkirajan, 2007).

PhysicalDatabase Model

Physicaldatabase modeldealwith theactualprocessof designingadatabase, based on therequirementsassembledin thelogicalphase.Alltheinformationcollectedischangedinto businessandrelational models.In thisprocessitemsare definedat a level referredto as a schema (Sumathi&amp Esakkirajan, 2007). Aschema is a groupof itemsthatareconnectedin thedatabase. Columnsandtablesare constructedbased on theinformationcollectedduring thelogicalphase.Users of thedata areprovidedwith an alternative view.To be ableto mapattributesto thecolumnsandtablesitwillbe importantto mapeachlogicaldomainof theelementto a physicaldata formandconstraints.Unlike a logicalmodel,physicalmodelis software specificandas suchthere are software constraints,featuresandrestrictionsneededforimplementation to supportthefunctionalneedof an application.

StructuredQueryLanguage

SQLsupportdatabases searchingandotherprocessesby applyingcommandssuchas ‘’print,’’‘’find,’’and‘’delete’’. Becausethesentencestructureof SQL is verysimilarto thenaturallanguageitpresentsusers with an affableandeasyto useinterface (Jones &ampJohnson, 2008).. Additionally eventhoughSQL solvedtheproblemof contractingan expertin programmingto be ableto access,adjustandstoredata in an organizedandefficientway,mostdatabase accessstillrequiresa trainedprogrammer. Thisis becausedata is theformof statisticalanalyses,scheduledreportsanddata entryprograms.

References

Albright,S. C. (2012). VBA for modelers: Developing decision supportsystems with Microsoft® Office Excel. Mason, OH: South-WesternCengage.

Domanski,P. (2000). Practical guide to relational database design: Frombusiness analysis via data modelling to. S.l.: Domanski-IrvineBook Comp.

Jones,J. and Johnson,E. (2008). A Developer’s Guide to Data Modellingfor SQL Server: Covering SQL Server. Addison-Wesley Professional.

Sumathi,S., &amp Esakkirajan, S. (2007). Fundamentals of relationaldatabase management systems. Berlin: Springer.