最新Chapter 8 Analyzing Systems Using Data Dictionaries教学讲义ppt.ppt

《最新Chapter 8 Analyzing Systems Using Data Dictionaries教学讲义ppt.ppt》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、Chapter8AnalyzingSystemsUsingDataDictionariesMajorTopicsDatadictionaryconceptsDefiningdataflowDefiningdatastructuresDefiningelementsDefiningdatastoresUsingthedatadictionaryDatadictionaryanalysisKendall&Kendall2©2005PearsonPrenticeHallDataDictionaryDatadictionaryisamainmethodforan

2、alyzingthedataflowsanddatastoresofdata-orientedsystems.Thedatadictionaryisareferenceworkofdataaboutdata(metadata).Itcollects,coordinates,andconfirmswhataspecificdatatermmeanstodifferentpeopleintheorganization.Kendall&Kendall3©2005PearsonPrenticeHallDataDictionaryContentsDatadicti

3、onariescontain:Dataflow.Datastructures.Elements.Datastores.Kendall&Kendall7©2005PearsonPrenticeHallDefiningDataFlowEachdataflowshouldbedefinedwithdescriptiveinformationanditscompositestructureorelements.Includethefollowinginformation:ID-identificationnumber.Label,thetextthatshoul

4、dappearonthediagram.Ageneraldescriptionofthedataflow.Kendall&Kendall8©2005PearsonPrenticeHallDefiningDataFlow(Continued)ThesourceofthedataflowThiscouldbeanexternalentity,aprocess,oradataflowcomingfromadatastore.ThedestinationofthedataflowTypeofdataflow,either:Arecordenteringorlea

5、vingafile.Containingareport,form,orscreen.Internal-usedbetweenprocesses.Kendall&Kendall9©2005PearsonPrenticeHallDefiningDataFlow(Continued)ThenameofthedatastructureorelementsThevolumeperunittimeThiscouldberecordsperdayoranyotherunitoftime.Anareaforfurthercommentsandnotationsabout

6、thedataflowKendall&Kendall10©2005PearsonPrenticeHallDataFlowExampleNameCustomerOrderDescriptionContainscustomerorderinformationandisusedtoupdatethecustomermasteranditemfilesandtoproduceanorderrecord.SourceCustomerExternalEntityDestinationProcess1,AddCustomerOrderTypeScreenDataStr

7、uctureOrderInformationVolume/Time10/hourCommentsAnorderrecordcontainsinformationforonecustomerorder.Theordermaybereceivedbymail,fax,orbytelephone.Kendall&Kendall11©2005PearsonPrenticeHallDefiningDataStructuresDatastructuresareagroupofsmallerstructuresandelements.Analgebraicnotati

8、onisusedtorepresentthedatastructure.Kend