CREATE UNIQUE INDEX index1 ON schema1.table1 (column1 DESC, column2 ASC, column3 DESC); 主要方案: 从Azure SQL 数据库和 Azure SQL 托管实例中的 SQL Server 2016(13.x)开始,可以在列存储索引上使用非聚集索引来提高数据仓库查询性能。 有关详细信息,请参阅 列存储索引 - 数据仓库。 有关其他类型...
CREATE TABLE (Transact-SQL) 從SQL Server 2016 (13.x) 開始,您可以建立具有資料行存放區索引的記憶體最佳化資料表。 建立資料表之後,也可以使用 ALTER TABLE ADD INDEX 語法來加入資料行存放區索引。 將資料載入資料行存放區索引。 列存儲索引資料載入 刪除列存放區索引。 DROP INDEX (Transact-SQL) 使用B ...
You cannot create a unique index on a single column if that column contains NULL in more than one row. Similarly, you cannot create a unique index on multiple columns if the combination of columns contains NULL in more than one row. These are treated as duplicate values for indexing purposes...
Requires ALTER permission on the table or view. User must be a member of the sysadmin fixed server role or the db_ddladmin and db_owner fixed database roles. Using SQL Server Management Studio to create an index with nonkey columns In Object Explorer, select the plus sign to expand the ...
Requires ALTER permission on the table or view. User must be a member of the sysadmin fixed server role or the db_ddladmin and db_owner fixed database roles. Using SQL Server Management Studio to create an index with nonkey columns In Object Explorer, select the plus sign to expand the ...
You cannot create a unique index on a single column if that column contains NULL in more than one row. Similarly, you cannot create a unique index on multiple columns if the combination of columns contains NULL in more than one row. These are treated as duplicate values for indexing purposes...
A constraint that provides entity integrity for a specified column or columns through a unique index. A table can have multiple UNIQUE constraints. UNIQUE can't be specified for CLR table-valued functions. CLUSTERED | NONCLUSTERED Indicate that a clustered or a nonclustered index is created for ...
A constraint that provides entity integrity for a specified column or columns through a unique index. A table can have multiple UNIQUE constraints. UNIQUE can't be specified for CLR table-valued functions. CLUSTERED | NONCLUSTERED Indicate that a clustered or a nonclustered index is created for ...
1CREATENONCLUSTEREDcolumnstoreINDEXPK__TestTable__ColumnStoreONTestTable(c1) 执行计划 在上面给出的文章里提到http://www.cnblogs.com/qanholas/archive/2013/03/08/2949205.html 下面几个SQL语句的执行计划也显示出列存储索引不会seek (2)列存储索引不支持 SEEK ...
And from the same Management menu, you can see the list and the data size of the columns from each participating table, that the SQL Server Engine touched when executing that query, with the number of the rows and if it is returned by the query or not, by clicking on the Columns optio...