SQL Trigger试图插入一个空值,但我的C#代码传递int 300？

Question

我需要对这个触发器上的错误提出一些看法.我在我的asp.net/c#应用程序中使用LINQ to SQL数据层,在添加此触发器之前将数据插入到数据库中.

我知道传递到数据层的值完全有效,因为我也在调试器中检查过它们.

我试图评估里程费用是否超过10,000的年度(英国纳税年度)限额,并根据不同的索赔率对其进行相应分配.

这是我的触发器

    USE [Horizon]
GO
/****** Object:  Trigger [dbo].[trER_InsteadOf_Insert]    Script Date: 07/22/2011 12:21:44 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:      Matthew Arnold
-- Create date: 19/07/2011
-- Description: Validate Expense Row for Allowed Mileage
-- =============================================
ALTER TRIGGER [dbo].[trER_InsteadOf_Insert] 
   ON  [dbo].[ExpenseRow] 
   INSTEAD OF INSERT
AS 
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    DECLARE @WorkerID varchar(20);
    DECLARE @ExpenseID int;
    DECLARE @Mileage int;
    DECLARE @Miles int;
    DECLARE @TotalMiles int;
    DECLARE @MilesOver10k int;
    DECLARE @MilesUnder10k int;
    DECLARE @Amount decimal (7, 2);
    DECLARE @AmountOver decimal(7, 2);
    DECLARE @ClaimedDate datetime;
    DECLARE @HighRateMileage decimal (7, 2);
    DECLARE @LowRateMileage decimal (7, 2);

    --Get current mileage and additional miles to work out threshold for worker expense
    SET @ExpenseID = (SELECT Expense_ID FROM inserted)
    SET @WorkerID = (SELECT Worker_ID FROM Expense WHERE Expense_ID = @ExpenseID)
    SET @Mileage = (SELECT Mileage FROM WorkerSettings WHERE Worker_ID = @WorkerID)
    SET @Miles = (SELECT Mileage FROM inserted)
    SET @ClaimedDate = (SELECT ExpenseDate From inserted)

    SET @HighRateMileage = (SELECT Value FROM dbo.SystemSettings WHERE ConfigType_ID = 1 
                            AND @ClaimedDate >=  StartDate
                            AND @ClaimedDate <= EndDate)
    SET @LowRateMileage =  (SELECT Value FROM dbo.SystemSettings WHERE ConfigType_ID = 2
                            AND @ClaimedDate >=  StartDate
                            AND @ClaimedDate <= EndDate)

    SET @TotalMiles = @Mileage + @Miles
    SET @MilesOver10k = @TotalMiles - 10000
    SET @MilesUnder10k = @Miles - @MilesOver10k

            IF (@Mileage < 10000)
                BEGIN
                    IF (@TotalMiles > 10000)
                        BEGIN
                            SET @AmountOver = @MilesOver10k * @LowRateMileage
                            SET @Amount = @MilesUnder10k * @HighRateMileage

                            --Split higher rate and lower rate mileage and insert two expense rows
                            INSERT INTO dbo.ExpenseRow (Expense_ID, JobNumber, ExpenseType_ID, Mileage,
                                                        ExpenseDate, Description, Amount, Notes, ClientChargeable,
                                                        VAT_Receipt, ItemAuthorised, AuthBy, 
                                                        CreatedBy, CreatedOn, ModifiedBy, ModifiedOn)

                            SELECT Expense_ID, JobNumber, ExpenseType_ID, @MilesOver10k, ExpenseDate,
                                                        Description, @AmountOver, 'Calculated at' + ' ' + @LowRateMileage + ' ' + 'pence per mile', 
                                                        ClientChargeable,
                                                        VAT_Receipt, 0, AuthBy, 
                                                        CreatedBy, CreatedOn, ModifiedBy, ModifiedOn FROM inserted



                            INSERT INTO dbo.ExpenseRow (Expense_ID, JobNumber, ExpenseType_ID, Mileage,
                                                        ExpenseDate, Description, Amount, Notes, ClientChargeable,
                                                        VAT_Receipt, ItemAuthorised, AuthBy, 
                                                        CreatedBy, CreatedOn, ModifiedBy, ModifiedOn)

                            SELECT Expense_ID, JobNumber, ExpenseType_ID, @MilesUnder10k, ExpenseDate,
                                                        Description, @Amount, 'Calculated at' + ' ' + @HighRateMileage + ' ' + 'pence per mile', 
                                                        ClientChargeable,
                                                        VAT_Receipt, 0, AuthBy, 
                                                        CreatedBy, CreatedOn, ModifiedBy, ModifiedOn FROM inserted


                        END
                    ELSE
                        BEGIN
                            --Insert higher rate into the expense row
                            INSERT INTO dbo.ExpenseRow (Expense_ID, JobNumber, ExpenseType_ID, Mileage,
                                                        ExpenseDate, Description, Amount, Notes, ClientChargeable,
                                                        VAT_Receipt, ItemAuthorised, AuthBy, 
                                                        CreatedBy, CreatedOn, ModifiedBy, ModifiedOn)

                            SELECT Expense_ID, JobNumber, ExpenseType_ID, Mileage,ExpenseDate, 
                                                        Description, Amount, 'Calculated at' + ' ' + @HighRateMileage + ' ' + 'pence per mile', 
                                                        ClientChargeable,
                                                        VAT_Receipt, 0, AuthBy, 
                                                        CreatedBy, CreatedOn, ModifiedBy, ModifiedOn FROM inserted


                        END

                END


            ELSE 

                    BEGIN
                        SET @AmountOver = @MilesOver10k * @LowRateMileage

                            --Insert lower rate mleage into the expense row
                            INSERT INTO dbo.ExpenseRow (Expense_ID, JobNumber, ExpenseType_ID, Mileage,
                                                        ExpenseDate, Description, Amount, Notes, ClientChargeable,
                                                        VAT_Receipt, ItemAuthorised, AuthBy, 
                                                        CreatedBy, CreatedOn, ModifiedBy, ModifiedOn)

                            SELECT Expense_ID, JobNumber, ExpenseType_ID, @Mileage,ExpenseDate, 
                                                        Description, @AmountOver, 'Calculated at' + ' ' + @LowRateMileage + ' ' + 'pence per mile', 
                                                        ClientChargeable,
                                                        VAT_Receipt, 0, AuthBy, 
                                                        CreatedBy, CreatedOn, ModifiedBy, ModifiedOn FROM inserted


                    END




END

很抱歉粘贴了这么多代码,但我很难过,但我缺乏经验显然造成了这个错误.

你能不能发现我的问题？

谢谢

Answer 1

你的触发器中有这一行:

SET @Mileage = (SELECT Mileage FROM WorkerSettings WHERE Worker_ID = @WorkerID)

所以,如果@WorkerID是null或者不存在,则@Mileage是要最终被null即使你为它应有的价值已经过了.这就是INSERT没有触发器的原因.