CREATE [ UNIQUE ] /*指定索引是否唯一*/ [ CLUSTERED | NONCLUSTERED ] /*索引的组织方式*/ INDEX index_name /*索引名称*/ ON {[ database_name. [ schema_name ] . |schema_name. ] table_or_view_name} ( column [ ASC | DESC ] [ ,...n ] ) /*索引定义的依据*/ [ INCLUDE ( column...
在CREATE INDEX 语句中使用 INCLUDE 子句,可以在创建索引时定义包含的非键列(即覆盖索引),其语法结构如下: CREATE NONCLUSTERED INDEX 索引名 ON { 表名| 视图名 } ( 列名 [ ASC | DESC ] [ ,...n ] ) INCLUDE (<列名1>, <列名2>, [,… n]) --创建非聚集覆盖索引 create nonclustered index No...
CREATENONCLUSTERED INDEX [IX_Employees2] ON [dbo].[Employees] ( [Emp_name] DESC ) GO 1. 2. 3. 4. 5. 6. 7. 在CREATE INDEX语句中使用INCLUDE子句,可以在创建索引时定义包含的非键列,其语法结构如下: 复制内容到剪贴板 代码: CREATENONCLUSTERED INDEX 索引名 ON { 表名| 视图名 } ( 列名 [...
Index_property: 索引属性。 UNIQUE索引既可以采用聚集索引结构,也可以采用非聚集索引的结构,如果不指明采用的索引结构,则SQL Server系统默认为采用非聚集索引结构。 1.42 删除索引语法: DROP INDEX table_name.index_name[,table_name.index_name] 说明:table_name: 索引所在的表名称。 index_name : 要删除的索引...
CREATE[UNIQUE][CLUSTERED|NONCLUSTERED]INDEXindex_nameON(column_name[ASC|DESC][,...n])[WITH<backward_compatible_index_option>[,...n]][ON{filegroup_name|"default"}]::={[database_name.[owner_name].|owner_name.]table_or_view_name}<backward_compatible_index_option>::={PAD_INDEX|FILLFACTOR...
mysql>create table test1(a int, b int, c char(20),primary key(a,b),unique key u_1(a,c),unique key u_2(b,c))shardkey=a; 此时有一个唯一索引u_2不包含 shardkey,无法创建表,会报如下错误: ERROR1105(HY000): A UNIQUE INDEX must include all columnsinthe table's partitioningfunction ...
SQL Entity Framework 6.1 - 使用INCLUDE语句创建索引 在本文中,我们将介绍如何在SQL Entity Framework 6.1中使用INCLUDE语句来创建索引。索引是数据库中提高查询性能的关键因素之一。通过使用INCLUDE语句,我们可以在创建索引时包含非键列,从而进一步优化查询性能。 阅
Index Characteristics After you have determined that an index is appropriate for a query, you can select the type of index that best fits your situation. Index characteristics include the following: Clustered versus nonclustered Unique versus nonunique ...
Index with included columnsA nonclustered index that is extended to include nonkey columns in addition to the key columns.Create Indexes with Included Columns Index on computed columnsAn index on a column that is derived from the value of one or more other columns, or certain deterministic input...
Index with included columnsA nonclustered index that is extended to include nonkey columns in addition to the key columns.Create Indexes with Included Columns Index on computed columnsAn index on a column that is derived from the value of one or more other columns, or certain deterministic input...