--创建测试表CREATETABLE[dbo].[TestUnique]([Id][int]IDENTITY(600000000,1)NOTFORREPLICATIONNOTNULL,[SiteId][int]NULL,[Url][nvarchar](420)NULL,[PublishOn][datetime]NULL,[AddOn][datetime]NULL,CONSTRAINT[PK_Archive]PRIMARYKEYCLUSTERED([Id]ASC)WITH(PAD_INDEX=ON, STATISTICS_NORECOMPUTE=OFF, IGNORE_...
--创建测试表CREATETABLE[dbo].[TestUnique]([Id][int]IDENTITY(600000000,1)NOTFORREPLICATIONNOTNULL,[SiteId][int]NULL,[Url][nvarchar](420)NULL,[PublishOn][datetime]NULL,[AddOn][datetime]NULL,CONSTRAINT[PK_Archive]PRIMARYKEYCLUSTERED([Id]ASC)WITH(PAD_INDEX=ON, STATISTICS_NORECOMPUTE=OFF, IGNORE_...
CREATE TABLE [dbo].[Users]( [ID] INT NOT NULL, [UserName] [datetime] NOT NULL, [Email] [varchar](50) NOT NULL, ) CREATE UNIQUE INDEX [ix_Users_UserName] ON Users --在UserName列上创建唯一索引,非聚集 ( [UserName] ) CREATE NONCLUSTERED INDEX ix_Users_Email ON Users --在Email列上创...
当决定是否创建一个唯一约束或者仅仅只是创建一个唯一索引时,请遵从MSDN库中的SQL SERVER文档: “There are no significant differences between creating a UNIQUE constraint and creating a unique index that is independent of a constraint. Data validation occurs in the same manner, and the query optimizer d...
so why can't non clustered index does the same thing by adding a suffix to duplicate row If you want to be able to add duplicate key values to a nonclustered index then simply omit the unique keyword in the CREATE INDEX. Behind the scenes SQL Server will still ensure it is unique in...
CREATEUNIQUECLUSTEREDINDEXxs_indONxsb(学号)WITHIGNORE_DUP_KEY 说明:如果表中已经存在一个聚集索引,则需要删除原来的索引,才能创建新索引. 6.1.3重建索引: ALTERINDEXALTERINDEX{索引名|ALL}ON表或视图{REBULLD……} 示例:重建kcb表上的所有索引: ALTERINDEXALLONkcbREBULLD ...
To create a unique index on a table, using: SQL Server Management Studio Transact-SQLBefore You BeginBenefits of a Unique IndexMulticolumn unique indexes guarantee that each combination of values in the index key is unique. For example, if a unique index is created on a combination of LastNa...
-- 创建唯一非聚集索引createuniquenonclustered--表示创建唯一非聚集索引indexUQ_NonClu_StuNo--索引名称onStudent(S_StuNo)--数据表名称(建立索引的列名)with ( pad_index=on,--表示使用填充fillfactor=50,--表示填充因子为50%ignore_dup_key=on,--表示向唯一索引插入重复值会忽略重复值statistics_norecompute=...
To create a unique index on a table, using: SQL Server Management Studio Transact-SQLBefore You BeginBenefits of a Unique IndexMulticolumn unique indexes guarantee that each combination of values in the index key is unique. For example, if a unique index is created on a combination of LastNa...
SQL Server唯一索引与NULL 唯一索引(Unique index)与唯一约束(UNIQUE constraint) 简介 唯一索引确保索引键列不包含重复值。 唯一索引可以由一列或多列组成。如果唯一索引有一列,则此列中的值将是唯一的。如果唯一索引有多个列,则这些列中的值组合是唯一的。