Primary Key - Clustered Index
in [Server Configuration]
|
Prev: SSMS doesn't see SSAS or Integration Services in server type drop
Next: HELP: A severe error occurred on the current command.
From: Alan T on 23 Mar 2010 02:13 Is the clustered index similar to the BTree structure?
From: Uri Dimant on 23 Mar 2010 02:59 Alan T CI and NCI have Btree structure "Alan T" <alan_NO_SPAM_pltse(a)yahoo.com.au> wrote in message news:%23GC83$kyKHA.5936(a)TK2MSFTNGP04.phx.gbl... > Is the clustered index similar to the BTree structure? >
From: Dan Guzman on 23 Mar 2010 07:41 > Is the clustered index similar to the BTree structure? Yes, the clustered is a b-tree structure similar to other indexes. The difference is that the clustered index leaf nodes are also the data actual pages. With non-clustered indexes, the leaf nodes refer to the data row using either the clustered index key (if the table has a clustered index) or the RID (table is a heap). -- Hope this helps. Dan Guzman SQL Server MVP http://weblogs.sqlteam.com/dang/
From: Jay Konigsberg on 23 Mar 2010 08:55
> Is the clustered index similar to the BTree structure? All indexes you can create in Microsoft SQL Server (and most indexes in all other databases) are implemented as b-tree's. We all get lazy with the notation these days, however, an index usually uses a "b-tree" and a clustered index uses a "b+-tree". The difference being that the + indicates a linked list at the leaf node that is used to logically order the data. As Erland already pointed out, Microsoft also placed the data in the leaf node of the b+-tree to implement the clustered index, which with the linked list and disk allocation algorithms, physically orders the data. If you Google "b-tree vs. b+ tree" you will get several university hits with class materials that describe it better. In particular http://db.ucsd.edu/CSE232W99/Indexing/index.htm seems like a very good set of pages. Good luck, Jay -- Jay Konigsberg SQL Server DBA in Sacramento, CA http://www.linkedin.com/in/jaykonigsberg Live in Sacramento, CA? Join the Sacramento SQL Server User Group on LinkedIn http://www.linkedin.com/groups?home=&gid=2825448&trk=anet_ug_hm&goback=%2Emyg "Alan T" <alan_NO_SPAM_pltse(a)yahoo.com.au> wrote in message news:%23GC83$kyKHA.5936(a)TK2MSFTNGP04.phx.gbl... > > |