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关系模式CSZ（CITY，ST，ZIP）其属性组上的函数依赖集为F=（CITY，ST）→ZIP，ZIP→CITY，关系模式CSZ的主属性是（）。
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建立一个供应商零件数据库其中供应商表SSnoSnameZipCity中的属性分别表示供应商代码供应商
1NF
2NF
3NF
BCNF
关系模式CSZCITYSTZIP其属性组上的函数依赖集为F={CITYST+ZIPZIP→CITY}
ZIP
CITY，ST，ZIP
CITY，ZIP
ST，ZIP
设有关系RCITYSTZIP其函数依赖集F={CITYSTZIPZIPCITY}则关系R至多满足
1NF
2NF
3NF
BCNF
存在某供应商表SSnoSnameZipCity其函数依赖集为Sno→SnameZipCityZip→
1NF
2NF
3NF
BCNF
关系模式CSZCITYSTZIP其属性组上的函数依赖集为F＝{CITYST→ZIPP→CITY}关系
ZIP
CITY，ST，ZIP
CITY，ZIP
ST，ZIP
关系模式CSZCITYSTZIP其属性组上的函数依赖集为F＝CITYST→ZIPZIP→CITY关系
ZIP
CITY，ST，ZIP
CITY，ZIP
ST，ZIP
所谓范式是指规范化的关系模式由于规范化的程度不同就产生了不同的范式在对关系模式进行规范化的过程中对1
非主属性对码的传递函数依赖
非主属性对码的部分函数依赖
主属性对码的部分和传递函数依赖
非平凡且非函数依赖的多值依赖
在对关系模式进行规范化的过程中对2NF关系进行投影得到一组3NF关系消除原关系中非主属性对码的
传递函数依赖
部分函数依赖和传递函数依赖
连接依赖
多值依赖
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Asocketisbasicallyanendpointofacommunicationlinkbetweentwoapplications.Socketsthatextendoveranetworkconnecttwoormoreapplicationsrunningoncomputersattachedtothenetwork.Asockettwoaddresses:.Socketsprovideacommunicationchannelbetweenoneormoresystems.TherearesocketsseparatelyusingTCPandUDP.
Microwavecommunicationuseshigh-frequency56wavesthattravelinstraightlinesthroughtheair.Becausethewavescannot57withthecurvatureoftheearththeycanbe58onlyovershortdistance.Thusmicrowaveisagood59forsendingdatabetweenbuildingsinacityoronalargecollegecampus.Forlongerdistancesthewavesmustberelayedbymeansofdishesor60.Thesecanbeinstalledontowershighbuildingsandmountaintops.
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MultipurposeInternetMailExtensionMIMEisa76documentmessagingstandardintheInternetenvironment.WithMIMEuserscansend77E-mailmessagesthatincludeaudiovideographicesandtexttoanyotheruserofaTCP/IPnetwork.Richtextinformationcanalsobe78intomessages.Itdefinesthefontsformatsand79featuresofadocumentsothedocumentcanbeeasily80onmanydifferenttypesofsystems.
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Thepurposeoftherequirementsdefinitionphaseistoproduceaclearcompleteconsistentandtestable36ofthetechnicalrequirementsforthesoftwareproduct.Duringtherequirementsdefinitionphasetherequirementsdefinitionteamusesaninterativeprocesstoexpandabroadstatementofthesystemrequirementsintoacompleteanddetailedspecificationofeachfunctionthatthesoftwaremustperformandeach37thatitmustmeet.Thestartingpointisusuallyasetofhighlevelrequirementsfromthe38thatdescribetheprojectorproblem.Ineithercasetherequirementsdefinitionteamformulatesanoverallconceptfor’thesystemandthendefines39showinghowthesystemwillbeoperatedpublishesthesystemandoperationsconceptdocumentandconductsasystemconceptreviewSCR.FollowingtheSCRtheteamderives40requirementsforthesystemfromthehighlevelrequirementsandthesystemandoperationsconceptusingstructuredorobject-orientedanalysis.Theteamspecifiesthesoftwarefunctionsandalgorithmsneededtosatisfyeachdetailedrequirement.
对有14个数据元素的有序表R-14]进行二分法查找查找到R[3]的关键码等于给定值此时元素比较顺序依次为
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