我有下表
CREATE TABLE [dbo].[LogFiles_Warehouse](
[id] [int] IDENTITY(1,1) NOT NULL,
[timestamp] [datetime] NOT NULL,
[clientNr] [int] NOT NULL,
[server] [nvarchar](150) COLLATE Latin1_General_CI_AS NOT NULL,
[storeNr] [int] NOT NULL,
[account] [nvarchar](50) COLLATE Latin1_General_CI_AS NOT NULL,
[software] [nvarchar](300) COLLATE Latin1_General_CI_AS NOT NULL,
CONSTRAINT [PK_Astoria_LogFiles_Warehouse] PRIMARY KEY CLUSTERED
(
[id] ASC
)WITH (PAD_INDEX = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
并希望避免表中出现重复的行。我想过在整个表上创建一个 UNIQUE 索引,但 SQL Manager Studio 告诉我这是不可能的,因为键太大。
除了索引之外,还有其他方法可以在所有列上强制执行唯一行吗?
最佳答案
在哈希值上创建一个UNIQUE
索引:
CREATE TABLE [dbo].[LogFiles_Warehouse]
(
[id] [int] IDENTITY(1,1) NOT NULL,
[timestamp] [datetime] NOT NULL,
[clientNr] [int] NOT NULL,
[server] [nvarchar](150) COLLATE Latin1_General_CI_AS NOT NULL,
[storeNr] [int] NOT NULL,
[account] [nvarchar](50) COLLATE Latin1_General_CI_AS NOT NULL,
[software] [nvarchar](300) COLLATE Latin1_General_CI_AS NOT NULL,
serverHash AS CAST(HASHBYTES('MD4', server) AS BINARY(16)),
accountHash AS CAST(HASHBYTES('MD4', account) AS BINARY(16)),
softwareHash AS CAST(HASHBYTES('MD4', software) AS BINARY(16))
)
CREATE UNIQUE INDEX
UX_LogFilesWarehouse_Server_Account_Software
ON LogFiles_Warehouse (serverHash, accountHash, softwareHash)
关于sql-server - SQL Server 中的唯一行约束,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9189705/