Sql 我应该使用此触发器中插入的表为可为空的外键设置默认值吗?
我有一个带有可为空FK字段的表。我使其为空以避免更改加载程序 为了实现(广告商)*1(货币),我写了一个简单的触发器:Sql 我应该使用此触发器中插入的表为可为空的外键设置默认值吗?,sql,sql-server,triggers,Sql,Sql Server,Triggers,我有一个带有可为空FK字段的表。我使其为空以避免更改加载程序 为了实现(广告商)*1(货币),我写了一个简单的触发器: ALTER TRIGGER InsertedAdvertisersDefaultCurrency ON dbo.Advertisers FOR INSERT AS UPDATE Advertisers SET Currency_Id=(SELECT TOP 1 Id FROM Currencies WHERE Name='USD') WHERE Curr
ALTER TRIGGER InsertedAdvertisersDefaultCurrency
ON dbo.Advertisers
FOR INSERT
AS
UPDATE Advertisers
SET Currency_Id=(SELECT TOP 1 Id FROM Currencies WHERE Name='USD')
WHERE Currency_Id=NULL
我的问题基本上是关于如何在每次插入时检查整个表中的空行
我觉得我应该使用插入的表(?)
这是桌子:
CREATE TABLE [dbo].[Advertisers](
[Id] [int] IDENTITY(1,1) NOT NULL,
[Name] [nvarchar](max) NOT NULL,
[Currency_Id] [int] NULL,
CONSTRAINT [PK_Advertisers] 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
ALTER TABLE [dbo].[Advertisers] WITH CHECK ADD CONSTRAINT [FK_CurrencyAdvertiser1] FOREIGN KEY([Currency_Id])
REFERENCES [dbo].[Currencies] ([Id])
GO
ALTER TABLE [dbo].[Advertisers] CHECK CONSTRAINT [FK_CurrencyAdvertiser1]
GO
是的,您应该只更新insertd记录:
UPDATE Advertisers
SET Currency_Id=(SELECT TOP 1 Id FROM Currencies WHERE Name='USD')
WHERE Id in (select Id from inserted)
也可以在该字段中使用默认值
ALTER TABLE [dbo].[Advertisers] ADD CONSTRAINT [DF_Advertisers_Currency_Id] DEFAULT ((101)) FOR [Currency_Id]
GO
其中101是美元id谢谢,这是一个很大的帮助,因为我原来的触发器甚至没有达到我预期的效果。哦,我认为我原来的触发器不起作用,因为我使用了“=null”,我应该使用“is null”。。。我总是犯错误,因为我大部分时间都在写c