因为聚集索引上有非聚集索引的依赖性,用单独的DROP INDEX 和 CREATE INDEX语句重建聚集索引将导致所有非聚集索引被重建两次(DROP,行定位器指向堆表数据行指针,CREATE行定位器指向新的聚集键值)。为了避免这种情况,使用CREATE INDEX语句的DROP_EXISTING子句来在一个单独的原子步骤中重建聚集索引。相似地,也可以在非聚集索...
SQL Server Native Client OLE DB 访问接口公开了IIndexDefinition::CreateIndex函数,从而允许使用者对 SQL Server 表定义新的索引。 SQL Server Native Client OLE DB 访问接口将表索引创建为索引或约束。SQL Server 向表所有者、数据库所有者和特定管理角色的成员提供了约束创建特权。默认情况下,只有表所有者才能对...
pIndexID參數可以是 NULL,如果是,SQL Server Native Client OLE DB 提供者會為索引建立唯一的名稱。 取用者可以在ppIndexID參數中指定 DBID 的有效指標,藉以擷取索引的名稱。 取用者可以將索引名稱指定為pIndexID參數uName聯集之pwszName成員中的 Unicode 字元字串。pIndexID的eKind成員必須是 DBKIND_NAME。
--BASIC EXAMPLE: Create a nonclustered index on a columnstore table.--Create the tableCREATETABLEt_account ( AccountKeyintNOTNULL, AccountDescriptionnvarchar(50), AccountTypenvarchar(50), UnitSoldint);--Store the table as a columnstore.CREATECLUSTERED COLUMNSTOREINDEXtaccount_cciONt_account;--Add ...
Create an indexed view: a T-SQL example The following example creates a view and an index on that view, in the AdventureWorks database. SQL Copy --Set the options to support indexed views. SET NUMERIC_ROUNDABORT OFF; SET ANSI_PADDING, ANSI_WARNINGS, CONCAT_NULL_YIELDS_NULL, ARITHABORT, ...
-- Set ONLINE = OFF to execute this example on editions other than Enterprise Edition. DROP INDEX AK_BillOfMaterials_ProductAssemblyID_ComponentID_StartDate ON Production.BillOfMaterials WITH (ONLINE = ON, MOVE TO NewGroup); GO -- Verify filegroup location of the moved table. SELECT t.name...
To specify a fill factor in an existing index In Object Explorer, connect to an instance of Database Engine. On the Standard bar, click New Query. Copy and paste the following example into the query window and click Execute. The example rebuilds an existing index and applies the specified ...
CREATETABLEMyTableKeyExample { Column1intIDENTITYPRIMARYKEYNONCLUSTERED, Column2int} 一旦创建了索引,改变它的唯一方法是删除和重建它,所以需要一开始就做对。 如果改变了聚集索引所在的列,那么SQL Server将需要对整个表完全重新排序(因为对于聚集索引,表的排列顺序和索引顺序是相同的)。
The SQL Server engine uses an index in much the same way a reader uses a book index. For example, one way to find all references to INSERT statements in a SQL book would be to begin on page one and scan each page of the book. We could mark each time we find the word INSERT unti...
查询的admissible index 是查询的一个或多个(在多列索引的情况下)可索引列上建立的索引。 workload的admissible index是工作负载中一个或多个查询的admissible index Example 1: Indexable Columns of a Query 考虑查询Q1: SELECT * FROM onektup, tenktup1 WHERE (onektup.unique1 = tenktup1.unique1) AND ...