Note:Although the index is created for only unique values, the original data in the table remains unaltered. Remove Index From Tables To removeINDEXfrom a table, we can use theDROP INDEXcommand. For example, SQL Server DROPINDEXColleges.college_index; PostgreSQL, Oracle DROPINDEXcollege_index; ...
Applies to:SQL ServerAzure SQL DatabaseAzure SQL Managed Instance Returns size and fragmentation information for the data and indexes of the specified table or view in the SQL Server Database Engine. For an index, one row is returned for each level of the B-tree in each partition. For a ...
For rowgroups in which 10% or more of the rows have been logically deleted, SQL Server tries to combine this rowgroup with one or more rowgroups. For example, rowgroup 1 is compressed with 500,000 rows and rowgroup 21 is compressed with the maximum of 1,048,576 rows. Rowgroup 21 ha...
SQL INSERT example, C-2 SQL*Loader example, C-3 loading thesaurus, 11-2 LOB columns loading, C-3 LOG_DIRECTORY system parameter, 2-74, 8-4 LOGFILENAME procedure, 8-4 logging index requests, 8-6 logical operators with NEAR, 3-32 LONG columns indexing, 1-22 long_wor...
在SQL Server 2012 (11.x) 和 SQL Server 2014 (12.x) 中,无法在列存储索引上创建非聚集索引。SQL 复制 --Create the table for use with this example. CREATE TABLE dbo.SimpleTable ( ProductKey [INT] NOT NULL, OrderDateKey [INT] NOT NULL, DueDateKey [INT] NOT NULL, ShipDateK...
其中包括用户定义类型变量或函数以及用户定义函数,但不能引用 Transact-SQL 语句。 partition_number 必须存在,否则,该语句将失败。 WITH ( <single_partition_rebuild_index_option> ) SORT_IN_TEMPDB、MAXDOPDATA_COMPRESSION 和XML_COMPRESSION 是在REBUILD 单个分区 (PARTITION = partition_number) 时可指定的选项。
Then, form an expression that involves table columns of the table_name in the ON clause. After defining an index expression, PostgreSQL will consider using that index when the expression appears in the WHERE clause or in the ORDER BY clause of the SQL statement. Note that maintaining indexes ...
Any function you specify incolumn_expressionmust return a repeatable value. For example, you cannot specify theSYSDATEorUSERfunction or theROWNUMpseudocolumn. Thecolumn_expressioncannot contain any aggregate functions. See Also: CREATE FUNCTIONandPL/SQL User's Guide and Reference ...
(DDL) operations on the source and pre-existing structures while the index operation is in progress. For example, this lock prevents concurrent rebuild of two indexes on the same table. Although this resource lock is associated with the Sch-M lock, it does not prevent data manipulation ...
在SQL Server 2012 (11.x) 和 SQL Server 2014 (12.x) 中,无法在列存储索引上创建非聚集索引。 SQL --Create the table for use with this example.CREATETABLEdbo.SimpleTable ( ProductKey [INT]NOTNULL, OrderDateKey [INT]NOTNULL, DueDateKey [INT]NOTNULL, ShipDateKey [INT]NOTNULL); GO--Cre...