结构E-R图。carnocwpacecarnamecwno车位carcolorcarmoncarsbcartalcaraddcarnocwnocaratcarinmontime停车记录caroutcwtypetimetypecwnocarnopiece收费记录moneypaycartime?carno车辆carcolorcarsb2、描述进行视图集成的具体过程,得到如下总体概念结构E-R图。cwnocwpacecarnocarmoncarsbcarnocarname停放carcolor车辆车位carsbcarcolor记载管理caraddcartalcarnocwnocarno收费记录carinpiececarout停车记录cartimemoneypaycwnotimetypemontimecwtype4ER图转换成关系模式4.1E-R图向关系模型的转换实体:车辆(carno,carsb,carcolor)carno是主码;车位(cwno,cwpace,carno,carname,carcolor,caradd,cartel,carmon)cwno是主码;收费记录(cwno,carno,cartime,moneypay,piece)cwno和carno是外码;停车记录(cwno,carno,carin,carout,timetype,cwtype,carat,montime)cwno和carno是外码;联系:管理(车辆,收费记录)停放(车辆,车位)记载(车位,停车记录)包含依赖关系如下:管理[carno]车辆[carno]管理[carno]收费记录[carno]停放[carno]车辆[carno]停放[carno]车位[carno]记载[carno]车位[carno]记载[carno]停车记录[carno]记载[cwno]车位[cwno]机子[cwno]停车记录[cwno]
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