在SQL Server 2008中强制执行唯一的日期范围字段

小编典典

在SQL Server 2008中强制执行唯一的日期范围字段

sql

首先，检查一下这个非常类似的问题：SQL Server2008中的唯一日期范围字段

上面的问题的答案是90％，我需要一个小口子，下面举个例子：

--#### Create example table
CREATE TABLE [dbo].[tbl_Example](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [StockCode] [varchar](20) NOT NULL,
    [ValidFrom] [datetime] NOT NULL,
    [ValidUntil] [datetime] NOT NULL,
    [Type] [char](1) NOT NULL,
 CONSTRAINT [PK_tbl_Example] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

--#### Add the trigger (based on David Halls answer - I allow duplicate date ranges as long as the StockCode or Type differ)
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TRIGGER [dbo].[DateRangeTrigger] ON [dbo].[tbl_Example]
    FOR INSERT, UPDATE
AS
    BEGIN
        IF EXISTS ( SELECT  t.ValidFrom ,
                            t.ValidUntil
                    FROM    tbl_Example t
                            JOIN inserted i ON ( i.StockCode = t.StockCode
                                                 AND i.Type = t.Type
                                                 AND i.ValidFrom > t.ValidFrom
                                                 AND i.ValidFrom < t.ValidUntil
                                                 AND i.id <> t.id
                                               )
                                               OR ( i.StockCode = t.StockCode
                                                    AND i.Type = t.Type
                                                    AND i.ValidUntil < t.ValidUntil
                                                    AND i.ValidUntil > t.ValidFrom
                                                    AND i.id <> t.id
                                                  )
                                               OR ( i.StockCode = t.StockCode
                                                    AND i.Type = t.Type
                                                    AND i.ValidFrom < t.ValidFrom
                                                    AND i.ValidUntil > t.ValidUntil
                                                    AND i.id <> t.id
                                                  ) ) 
            BEGIN
                RAISERROR ('Date range cant overlap existing date ranges for given StockCode and Type', 16, 1)
                IF ( @@TRANCOUNT > 0 ) 
                    ROLLBACK
            END
    END
GO

--#### Problem: its allowing duplicate date ranges where Start and End Dates are 100% equal
INSERT [dbo].[tbl_Example] ([StockCode], [ValidFrom], [ValidUntil], [Type]) VALUES (N'Test', CAST(0x0000A13900000000 AS DateTime), CAST(0x0000A13B00000000 AS DateTime), N'O')
INSERT [dbo].[tbl_Example] ([StockCode], [ValidFrom], [ValidUntil], [Type]) VALUES (N'Test', CAST(0x0000A13900000000 AS DateTime), CAST(0x0000A13B00000000 AS DateTime), N'O')

你会注意到，与戴维鈥檚扳机的地方，我仍可以插入日期重叠如果任一[ValidFrom]或者[ValidUntil]是 相等的 。

OR缺少向触发器添加更多子句以说明匹配开始或匹配结束或两者兼而有之的方式-调整触发器以防止出现最后一个子句的最简单方法是什么？

阅读 149

2021-05-16

共1个答案

小编典典

我认为这种情况更合适：

IF EXISTS ( SELECT  * --No need to choose columns in an EXISTS
        FROM    tbl_Example t1
         inner join
                tbl_Example t2
                  on
                     t1.StockCode = t2.StockCode and
                     t1.Type = t2.Type and
                     t1.ValidFrom < t2.ValidTo and
                     t2.ValidFrom < t1.ValidTo and
                     t1.ID <> t2.ID
        where
            t1.ID in (select ID from inserted))
BEGIN
     RAISERROR ('Date range cant overlap existing date ranges for given StockCode and Type', 16, 1)
     ROLLBACK --We're in a trigger, we *must* be in a transaction
END

它使用更简单的条件来检测重叠-如果两行都在另一行结束之前开始，则存在重叠。

2021-05-16