计算机专业英的教学辅导精选

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1、《计算机专业英语》教学辅导2第4－6章Chapter4DatabaseSystems4.1ABriefIntroductiontoDatabaseSystems课文主要介绍了数据库的基本概念（如表、列、行、字段和记录）及其结构；数据库系统的概念及其发展历史。1.重点句子Adatabaseisacollectionofinformationthatisrelatedtoasubjectorpurpose.Withinthedatabase,youorganizethedataintotables.Tablesaremadeupofcolumnsandrows.Columnsrepresenti

2、ndividualfieldsinatable.Rowsrepresentrecordsofdatainatable.Eachfieldinthetablecontainsonepieceofinformation.Eachrecordrepresentsonesetofrelatedinformation.Thenumberofrowsinatablerepresentsthetotalnumberoftablerecords.Databaseitselfdoesnotrefertoasystem.2．在发展历史的回顾中提及的是：Amodel:13rulesdefinedbyDr.Codd

3、forrelationaldatabasedesign.Twotechnologies:PersonalcomputerandLANApopulartypeofdatabasesystem:client/serversystem3．在课文中，有需要做些解释的地方。（1）Itwascalledclient/serversystemandisstillinwideuse.注意这里动词的时态。（2）应注意database和databasesystem的区别。4．PhrasesandExpressionsdatabase（DB）数据库databasetable数据表onesetof一系列tabler

4、ecord表记录databasesystem数据库系统relationaldatabase关系型数据库client/server客户机/服务器4.2DifferentTypesofDatabases课文主要介绍了两种类型(flat-file,relational)的数据库及其优缺点。1．重点句子Theflat-filestyleofdatabaseisidealforsmallamountsofdatathatneedstobehumanreadableoreditedbyhand.Oneofthemainproblemswithusingflatfilesforevenasmalldata

5、baseisthefactthatitisveryeasytobedestroyed.Tablescanbeusedtorepresentrealworldobjects,witheachfieldactinglikeanattribute.The"relation"comesfromthefactthatthetablescanbelinkedtoeachother,forexampletheauthorofabookcouldbelinkedtotheauthorstabletoprovidemoreinformationabouttheauthor.Onemajoradvantageo

6、ftherelationalmodelisthat,ifadatabaseisdesignedefficiently,thereshouldbenoduplicationofanydata;helpingtomaintaindatabaseintegrity.Relationaldatabasesalsohavefunctions"builtin"thathelpthemtoget,sortandeditthedatainmanydifferentways.2．在课文中，有几个句子需要做些解释。（1）…nottomentionhow…,更不用说……。（2）Havingsaidthat,joi

7、ninglargetablestoeachothertogetthedatarequiredforaquerycanbequiteheavyontheprocessor.提示请参见教材。（3）Ifthedataissimpleenough,thiscouldbeacomma,butmorecomplexstringsareusuallyseparatedusingtabs,newlinesoracombina