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1、一、ConsiderthefollowinginformationinanairportdatabaselAnairportisdescribedbyitsnameandthecitythattheairportlocatesatlEachairplanehasaregistrationnumberandthedateofproductionasitsdescriptiveattributeslEachairplanemodelisidentifiedbyamodelnumberandhasacapacityandaweightlAtechnicianischaracterizedby
2、technician_id,hisnameandhisphonenumberlEachairportaccommodatesanumberofairplanemodels,andanairplanemodelmayappearsinseveralairportslEachairplaneisofaspecificmodel,e.g.Boeing737;andforeachmodel,theremaybemorethanoneairplanebeingofitlAnumberoftechniciansworkattheairport,buteachtechnicianworksatonl
3、yoneairport.lEachtechnicianisresponsibleforoneormoreplanemodels,andoneplanemodelhasoneormoretechniciansresponsibleforitlEachairplaneisperiodicallytestedbyanumberoftechnicianstoensurethattheairplaneisstillairworthy.Atechnicianmaytestseveralairplaneseachyear.Itisrequiredthatwhenatechniciantestsana
4、irplane,theairplanemodelthatheisresponsibleforisjustthemodelthattheairplanetestedisof.Theinformation,suchastestnumber,thetestingdate,thetestingresultandthetimespentonthetest,isneededtodescribeatestingoftheairplane(1)DesigntheE/Rdiagramfortheairportdatabaseonthebasisoftheinformationmentionedabove
5、Note:thekeyoftheentities,mappingcardinalityofeachrelationshipandparticipationofeachentitytotherelationshipshouldbedescribedinthediagram..(10points)(2)ConverttheE-Rdiagramtotheproperrelationalschema,andgivetheprimarykeyofeachrelationschemabyunderlines.(10points)Answers：或：(2)(10points)实体airport归结为
6、:airport(a-name,city);实体model归结为:model(m-num,weight,capacity);联系accommodate归结为:accommodate(a-name,m-num);实体airplane和联系be-of归结为：airplane(re-num,date,m-num);实体technician、联系work、联系test归结为：technician(t-id,t-name,phone-num,a-name)test(t-id,re-num,t-num,t-date,time,result)联系responsible归结为responsible(t
7、-id,m-num)如果technician部分参与到联系test中，则如下图所示：关系表转换：实体airport归结为:airport(a-name,city);实体model归结为:model(m-num,weight,capacity);联系accommodate归结为:accommodate(a-name,m-num);实体airplane和联系be-of归结为：airplane(re-num,date,m-num);实体technic
