在 SQL Server 2005 中创建触发器(也必须在 2008 中工作)以防止重复?
我有一个表,我使用以下查询插入数据(来自 c# 代码):
INSERT INTO [BazaZarzadzanie].[dbo].[Wycena]
([KlienciPortfeleKontaID]
,[WycenaData]
,[WycenaTyp]
,[WycenaWartosc]
,[WycenaWaluta]
,[WycenaUzytkownik]
,[WycenaUzytkownikData])
VALUES
(@varKlienciPortfeleKontaID
,@varWycenaData
,@varWycenaTyp
,@varWycenaWartosc
,@varWycenaWaluta
,@varWycenaUzytkownik
,@varWycenaUzytkownikData)
表创建脚本如下所示:
CREATE TABLE [dbo].[Wycena](
[KlienciPortfeleKontaID] [int] NULL,
[WycenaData] [datetime] NULL,
[WycenaTyp] [int] NULL,
[InID] [int] NULL,
[WycenaIlosc] [decimal](18, 2) NULL,
[WycenaCena] [decimal](18, 2) NULL,
[WycenaWartosc] [decimal](18, 2) NULL,
[WycenaWaluta] [nvarchar](3) NULL,
[WycenaUzytkownik] [nvarchar](50) NULL,
[WycenaUzytkownikData] [datetime] NULL
) ON [PRIMARY]
它还有几个外键,但我无法创建主/唯一键。所以我想防止重复,我会使用触发器,因为要知道一行是重复的,我实际上必须测试该行的每个值(也许不是最后两列)?该表大约有 200 万行。
这是个好主意吗?或者有更好的方法吗?
以下是我创建的触发器(未测试是否有效):
CREATE TRIGGER [dbo].[trg_WycenaDuplicateCheck]
ON [dbo].[Wycena] FOR INSERT
AS
IF EXISTS(SELECT INSERTED.[KlienciPortfeleKontaID]
,INSERTED.[WycenaData]
,INSERTED.[WycenaTyp]
,INSERTED.[InID]
,INSERTED.[WycenaIlosc]
,INSERTED.[WycenaCena]
,INSERTED.[WycenaWartosc]
,INSERTED.[WycenaWaluta]
FROM INSERTED, Wycena
WHERE INSERTED.[KlienciPortfeleKontaID] = Wycena.[KlienciPortfeleKontaID]
AND INSERTED.[WycenaData] = Wycena.[WycenaData]
AND INSERTED.[WycenaTyp] = Wycena.[WycenaTyp]
AND INSERTED.[InID] = Wycena.[InID]
AND INSERTED.[WycenaIlosc] = Wycena.[WycenaIlosc]
AND INSERTED.[WycenaCena] = Wycena.[WycenaCena]
AND INSERTED.[WycenaWartosc] = Wycena.[WycenaWartosc]
AND INSERTED.[WycenaWaluta] = Wycena.[WycenaWaluta]
Group By INSERTED.[KlienciPortfeleKontaID]
,INSERTED.[WycenaData]
,INSERTED.[WycenaTyp]
,INSERTED.[InID]
,INSERTED.[WycenaIlosc]
,INSERTED.[WycenaCena]
,INSERTED.[WycenaWartosc]
,INSERTED.[WycenaWaluta]
HAVING COUNT (*) > 1)
BEGIN
RAISERROR('>>>DUPLICATES PREVENTED<<< ',10,1)
ROLLBACK TRAN
END
I have table that I insert data with following query (from c# code):
INSERT INTO [BazaZarzadzanie].[dbo].[Wycena]
([KlienciPortfeleKontaID]
,[WycenaData]
,[WycenaTyp]
,[WycenaWartosc]
,[WycenaWaluta]
,[WycenaUzytkownik]
,[WycenaUzytkownikData])
VALUES
(@varKlienciPortfeleKontaID
,@varWycenaData
,@varWycenaTyp
,@varWycenaWartosc
,@varWycenaWaluta
,@varWycenaUzytkownik
,@varWycenaUzytkownikData)
Table creation script looks like this:
CREATE TABLE [dbo].[Wycena](
[KlienciPortfeleKontaID] [int] NULL,
[WycenaData] [datetime] NULL,
[WycenaTyp] [int] NULL,
[InID] [int] NULL,
[WycenaIlosc] [decimal](18, 2) NULL,
[WycenaCena] [decimal](18, 2) NULL,
[WycenaWartosc] [decimal](18, 2) NULL,
[WycenaWaluta] [nvarchar](3) NULL,
[WycenaUzytkownik] [nvarchar](50) NULL,
[WycenaUzytkownikData] [datetime] NULL
) ON [PRIMARY]
It also has couple of foreign keys but nothing that i could make primary/unique key. So i thought to prevent duplicates i would go for a trigger since to know one row is duplicate i actually have to test every single value of that row (well maybe not 2 last columns) ? This table has around 2mln rows.
Is this good idea? Or is there a better way?
Below is trigger I've created (not tested if it works):
CREATE TRIGGER [dbo].[trg_WycenaDuplicateCheck]
ON [dbo].[Wycena] FOR INSERT
AS
IF EXISTS(SELECT INSERTED.[KlienciPortfeleKontaID]
,INSERTED.[WycenaData]
,INSERTED.[WycenaTyp]
,INSERTED.[InID]
,INSERTED.[WycenaIlosc]
,INSERTED.[WycenaCena]
,INSERTED.[WycenaWartosc]
,INSERTED.[WycenaWaluta]
FROM INSERTED, Wycena
WHERE INSERTED.[KlienciPortfeleKontaID] = Wycena.[KlienciPortfeleKontaID]
AND INSERTED.[WycenaData] = Wycena.[WycenaData]
AND INSERTED.[WycenaTyp] = Wycena.[WycenaTyp]
AND INSERTED.[InID] = Wycena.[InID]
AND INSERTED.[WycenaIlosc] = Wycena.[WycenaIlosc]
AND INSERTED.[WycenaCena] = Wycena.[WycenaCena]
AND INSERTED.[WycenaWartosc] = Wycena.[WycenaWartosc]
AND INSERTED.[WycenaWaluta] = Wycena.[WycenaWaluta]
Group By INSERTED.[KlienciPortfeleKontaID]
,INSERTED.[WycenaData]
,INSERTED.[WycenaTyp]
,INSERTED.[InID]
,INSERTED.[WycenaIlosc]
,INSERTED.[WycenaCena]
,INSERTED.[WycenaWartosc]
,INSERTED.[WycenaWaluta]
HAVING COUNT (*) > 1)
BEGIN
RAISERROR('>>>DUPLICATES PREVENTED<<< ',10,1)
ROLLBACK TRAN
END
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在您关心的字段上创建“唯一”索引。
Create a "unique" index on the fields you care about.
似乎您需要查看唯一约束
Seems like you need to look at UNIQUE Constraints