CREATE INDEX index_name on table_name (column1, column2) 隐式索引(Implicit Indexes)# 当创建primary key constraints and unique constraints.时会自动创建隐士索引 全文索引# 一种特殊类型的基于标记的功能性索引,由Microsoft SQL Server全文引擎生成和维护。用于帮助在字符串数据中搜索复杂的词。这种索引的结构...
create index idx2 on Person.Person(FirstName)涵盖索引涵盖索引算是使用率最高的索引类型,建立索引时透过include子句来扩充非索引键字段,SQL Server会将非索引键字段存放在索引上的分叶阶层 (不会每一笔索引列都存在),该层级几乎可说是索引叶上的最末层,且include只支持非丛集索引类型,涵盖字段有以下特性:...
如果SQL Server只运行了很短的一段时间,你可能不想去使用一些dmv统计数据,因为他们并不是一个能够代表SQL Server实例可能遇到的真实工作负载的样本。另一方面,SQL Server只能维持一定量的信息,有些信息在进行SQL Server性能管理活动的时候可能丢失,所以如果SQL Server已经运行了相当长的一段时间,一些统计数据就有可能已...
針對記憶體最佳化資料表的 Transact-SQL INSERT 和 SELECT 陳述式與一般資料表無異。適用於記憶體最佳化資料表的 ALTER TABLEALTER TABLE...ADD/DROP 可以從記憶體最佳化資料表或索引新增或移除資料行。CREATE INDEX 和 DROP INDEX 無法針對記憶體最佳化資料表執行,請改用 ALTER TABLE ...ADD/DROP ...
In addition to the features I will describe here, there are many other important enhancements to T-SQL that I will not cover in depth because some are not new conceptually while others deserve independent coverage. These include messaging and the Service Broker platform, partitioning, and XML enh...
To complete this tutorial, you don't have to know the SQL language, but you should understand basic database concepts such as tables. During this tutorial, you will create a database and create a Windows user. These tasks require a high level of permissions; therefore, you should log in ...
To resolve this issue, include the column that is tested as NULL in the returned columns. Or, add this column as include columns in the index. SQL CREATENONCLUSTEREDINDEXNew_i_action_filt_action_date_typeONdbo.filter_test (action_type)include(action_date)WHEREaction_dateISNULL...
The query tag supports the standard SQL statement SELECT. Put the query tag just after the driver tag. To query the database for all the CD data: In the ProductList page, just following the driver tag, create a query to select all the CD data from the database: ...
In SQL Server 2008, the type of events on which you can now create DDL triggers is enhanced to include stored procedures that perform DDL-like operations. This gives you more complete coverage of DDL events that you can capture with triggers. The XML schema for events is installed as part...
在SQL Server 或 Azure SQL 数据库中的当前数据库中创建别名数据类型或用户定义类型。 别名数据类型的实现基于数据库引擎本机系统类型。 用户定义类型通过 Microsoft.NET Framework 公共语言运行时 (CLR) 中的程序集的类来实现。 若要将用户定义的类型绑定到其实现,必须先使用 CREATE ASSEMBLY 在数据库引擎中注册...