【正文】 代碼：ALTER trigger [dbo].[Trigger_deleteCar_subtractCarClassCnt]on [dbo].[Table_Car]after deleteasbeginupdate Table_CarClassset CarClassCnt = CarClassCnt 1where CarClassNo in (select CarClassNo from deleted)end28 / 55 Trigger_updateCar觸發(fā)器類型：update功能：在修改汽車租賃狀態(tài)時(shí)，對應(yīng)類別的庫存相應(yīng)的加減一所屬表：Table_Car代碼：ALTER trigger [dbo].[Trigger_updateCar]on [dbo].[Table_Car]after updateasif(UPDATE(CarSta))beginupdate Table_CarClassset CarClassCnt = CarClassCnt 1where CarClassNo in(select from inserted,deleted where = and = 0 and = 1)update Table_CarClassset CarClassCnt = CarClassCnt + 1where CarClassNo in(select from inserted,deleted where = and = 1and = 0)end Trigger_updateRecordReturnDate觸發(fā)器類型：update功能：在更新還車時(shí)間時(shí)，更新實(shí)際花費(fèi)所屬表：Table_Record代碼：ALTER trigger [dbo].[Trigger_updateRecordReturnDate]on [dbo].[Table_Record]after updateasdeclare @price moneyif(UPDATE(RecordReturnDate))29 / 55beginselect @price = (select CarClassDayPrice1 from Table_CarClass where CarClassNo in (select CarClassNo from Table_Car where CarNo in (select from inserted,deleted where = and ( is null) and ( is not null))))update Table_Recordset RecordCost = @price * (DATEDIFF(DAY,RecordRentDate,RecordReturnDate)+1)where RecordNo in (select from inserted,deleted where = and ( is null) and ( is not null))end七、 運(yùn)行結(jié)果 租賃汽車圖 租賃汽車30 / 55 資料查詢圖 資料查詢 訂單查詢圖 訂單查詢31 / 55 查詢一類汽車圖 查詢一類汽車 還車登記圖 還車登記32 / 55 統(tǒng)計(jì)某一年齡最喜歡的類型圖 統(tǒng)計(jì)某一年齡最喜歡的類型八、 總結(jié)通過這次實(shí)訓(xùn)熟悉了 Sql Server 2022 的使用，進(jìn)一步了解了數(shù)據(jù)庫的設(shè)計(jì)，能更加熟練的使用 Sql Server 來完成一些數(shù)據(jù)的存儲和查詢。因?yàn)閷τ|發(fā)器不怎么熟悉，在建立觸發(fā)器時(shí)遇到了一些困難，通過查閱相關(guān)書籍學(xué)會了觸發(fā)器的語法，攻克了這個(gè)難題，對于 Sql Server 2022 中觸發(fā)器主要是要理解好 inserted 表和 deleted 表。因?yàn)橛幸粋€(gè)功能要根據(jù)年齡分類查詢，而我存儲的信息中只有身份證號碼，所以我需要一個(gè)函數(shù)直接根據(jù)身份證號碼算出年齡，一開始覺得可能不好寫，不過看了幾個(gè)例子后發(fā)現(xiàn)函數(shù)和存儲過程并沒有什么不同，只是多了個(gè)返回值而已。實(shí)訓(xùn)的過程中一直磕磕碰碰，因?yàn)橄雽懡缑?，而我只?C 和 C++，所以用到了 Qt 庫，但接觸時(shí)間不長所以沒能寫出界面，是有點(diǎn)遺憾，于是在寫了個(gè)控制臺程序，也算模擬一下界面把。困難總是會碰到的，但只要有決心，問題總會在某個(gè)時(shí)候迎刃而解。33 / 55九、 附錄 存儲過程代碼 proc_insert_CarALTER proc [dbo].[proc_insert_Car]@CarNo char(10),@CarClassNo char(4),@CarSta bit = 1,@CarDate datetime,@CarColor char(15)asif(not exists (select * from Table_Car where CarNo = @CarNo))begininsert into Table_Carvalues(@CarNo,@CarClassNo,@CarSta,@CarDate,@CarColor)return 1endelse return 0 proc_insert_CarClassALTER proc [dbo].[proc_insert_CarClass]@CarClassNo char(4),@CarClassBrand char(10),@CarClassSeat smallint,@CarClassCnt int = 0,@CarClassDayPrice1 money,@CarClassDayPrice2 money,@CarClassMonthPrice moneyasif(not exists (select *from Table_CarClass where CarClassNo = @CarClassNo))begininsert into Table_CarClassvalues(@CarClassNo,@CarClassBrand,@CarClassSeat,@CarClassCnt,@CarClassDayPrice1,@CarClassDayPrice2,@CarClassMonthPrice)。return 1endelse return 0。34 / 55 proc_insert_CustomerALTER proc [dbo].[proc_insert_Customer]@CusNo char(20),@CusPassword char(20),@CusName char(20),@CusSex char(2),@CusPhone char(15),@CusCompany char(40)asif(not exists(select * from Table_Customer where CusNo = @CusNO or CusPhone = @CusPhone))begininsert into Table_Customervalues(@CusNo,@CusPassword,@CusName,@CusSex,@CusPhone,@CusCompany)return 1endelse return 0 proc_insert_RecordALTER proc [dbo].[proc_insert_Customer]@CusNo char(20),@CusPassword char(20),@CusName char(20),@CusSex char(2),@CusPhone char(15),@CusCompany char(40)asif(not exists(select * from Table_Customer where CusNo = @CusNO or CusPhone = @CusPhone))begininsert into Table_Customervalues(@CusNo,@CusPassword,@CusName,@CusSex,@CusPhone,@CusCompany)return 1endelse return 0 proc_insert_WorkerALTER proc [dbo].[proc_insert_Worker]@WorkNo char(5),@WorkPassword char(20),35 / 55@workName char(20),@workSex char(2),@workPhone char(15)asif(not exists(select * from Table_Worker where WorkNo = @WorkNO))begininsert into Table_Workervalues(@WorkNo,@WorkPassword,@workName,@workSex,@workPhone)return 1endelse return 0 proc_find_AllCarClassALTER proc [dbo].[proc_find_AllCarClass]asbeginselect * from Table_CarClassreturn @@rowcountend proc_find_CarALTER proc [dbo].[proc_find_Car]@CarNo char (10)asbeginselect * from Table_Car where CarNo = @CarNoreturn @@rowcountend proc_find_CarsALTER proc [dbo].[proc_find_Cars]@CarClassNo char(4)asbeginselect * from Table_Car where CarClassNO = @CarClassNoreturn @@rowcountend36 / 55 proc_find_CarRecordALTER proc [dbo].[proc_find_CarRecord]@CarNo char(10)asbeginselect * from Table_Record where CarNo = @CarNoreturn @@rowcountend proc_find_CustomerALTER proc [dbo].[proc_find_Customer]@CusNo char(18)asbeginselect * from Table_Customer where CusNo = @CusNoreturn @@rowcountend proc_find_CustomerFavoriteALTER proc [dbo].[proc_find_CustomerFavorite]@CusAge intasbeginselect *from Table_CarClasswhere CarClassNo in(select CarClassNofrom Table_Record,Table_Carwhere = and () = @CusAgegroup by CarClassNo having count(*) = all(select count(CarClassNo)from Table_Record,Table_Carwhere = and () = @CusAge37 / 55group by CarClassNO))return @@rowcountend proc_find_CustomerRecordALTER proc [dbo].[proc_find_CustomerRecord]@CusNo char(18)asbeginselect * from Table_Record where CusNo = @CusNoreturn @@rowcountend 管理系統(tǒng)代碼 ifndef LOGINdefine LOGINint menu_main()。int menu_login()。int menu_regist()。int menu_Customer()。int menu_Worker()。int menu_findCar()。int menu_findUser()。int menu_findUserRecord()。int menu_findUserFavorite()。int menu_rentCar()。int menu_returnCar()。endif // LOGIN38 / 55 include stringinclude QStringListusing std::string。ifndef USESQL_Hdefine USESQL_Hstruct Customer{ QString CusNo。 QString CusPassword。 QString CusName。 QString CusSex。 QString CusPhone。 QString CusCompany。}。bool sql_connect()。bool sql_f