server index

Transferred from: http://www.cnblogs.com/chenmh/p/3785285.htmlInclude column indexOverviewThe Include column index is also a nonclustered index, and the index structure is the same as the clustered index structure, where the non-key column

What is an index?An index is a data structure on a disk that is based on a table or view. Using an index can make data acquisition faster and higher in universities, and also affect some other performance, such as inserting or updating.There are two

IndexWhat is an index?An index is a data structure on a disk that is based on a table or view. Using an index can make data acquisition faster and higher in universities, and also affect some other performance, such as inserting or updating.There

The basics of SQL Server indexing are generally understood by understanding the relevant knowledge.Index is to optimize the query efficiency, too many duplicate indexes will affect the data deletion and modification operations. So the use of the

Declare qc_cursor cursor SCROLL optimistic forSelect SiteName from Tb_vhostcheckOpen Qc_cursordeclare @siteName nvarchar (50)While @ @fetch_status =0Begin FETCH NEXT from Qc_cursor to @siteName--print @siteNameIf not exists (select 1 from vhhostlist

Create a sample Table first TempCreate an index on the Name field in a table if exists (select name from sysindexes where name = " Span style= "color: #800000;" >suoyin " ) DROP INDEX Temp.suoyin ----- When the index was created correctly,

Original: SQL Server index and Table Architecture (ii)Nonclustered indexesOverviewfor nonclustered indexes, the information involved is a bit more than the clustered index, because the entire length of the page is much more involved in the next

transferred from: http://www.cnblogs.com/knowledgesea/p/3672099.htmlThe concept of an indexThe purpose of the index: our data query and processing speed has become a measure of the success of the application system standards, and the use of indexes

In the application system, especially in the online thing processing system, the data query and processing speed have become the standard to measure the application system.The use of index to speed up the data processing speed has become the

1.1.1 SummaryIf we want to optimize the database, we can mainly use the following five methods to optimize the database system.1. Computer Hardware tuning2. Application Tuning3. Database Index Optimization4. SQL statement Optimization5. Transaction

SQL Server Index1. Clustered and nonclustered indexesClustered index: Sorted by clustered index, nonclustered indexes are faster than nonclustered indexes because they are not sorted by index key (one table has only one clustered index)2. Unique and

First, the basic concept of indexed viewsAn indexed view is actually a view that "materialized" a set of unique values into a clustered index, which is materialized almost as a table, and its data is stored in one copy (it consumes hard disk space,

Start from Create By using the explicit CREATE INDEX command As an implied object when creating a constraint Implicit indexes created with constraintsAn implicit index is created when you add one of the following two constraints to

clustered index, nonclustered index, nonclustered unique indexWe all know that establishing an appropriate index can improve query speed and optimize queries. First, whether a clustered or nonclustered index is a B-tree structure . The

Start from Create By using the explicit CREATE INDEX command As an implied object when creating a constraint Implicit indexes created with constraintsAn implicit index is created when you add one of the following two constraints to

Indexes do not always take effect, such as the following, which will invalidate the index : If there is an or in the condition, it will not be used even if there is a conditional index ( which is why the use of or is minimized ) 　　Note: If

In a database with a large number of transactions, tables and indexes are fragmented over time. Therefore, to improve performance, you should periodically check the fragmentation of tables and indexes, and defragment them with a lot of fragmentation.

first, the basic concept of indexed viewsAn indexed view is actually a view that "materialized" a set of unique values into a clustered index, which is materialized almost as a table, and its data is stored in one copy (it consumes hard disk space,

Original: SQL Server index and table architecture (i)Clustered indexOverviewThe concept of index and table architecture has always been the discussion of a lot of topics, including the table of various storage forms is the focus of discussion, on

Original: SQL Server index and table Architecture (III)Include column indexOverviewThe include column index is also a nonclustered index, and the index structure is the same as the clustered index structure, where the non-key column containing the