SQL Server Forums
Profile | Register | Active Topics | Members | Search | Forum FAQ
 
Register Now and get your question answered!
Username:
Password:
Save Password
Forgot your Password?

 All Forums
 General SQL Server Forums
 New to SQL Server Administration
 clustured index question
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

aakcse
Aged Yak Warrior

India
570 Posts

Posted - 06/27/2009 :  16:00:33  Show Profile  Reply with Quote
Hi all,
I have a question.

When we have clustured index on a table, then entire row is stored at the leaf level, then

Wht is the significance of creating normal index on other column of the same table which has clustured index.

Regards,
aak

webfred
Flowing Fount of Yak Knowledge

Germany
8765 Posts

Posted - 06/27/2009 :  17:33:50  Show Profile  Visit webfred's Homepage  Reply with Quote
If you want to search often for that other column this "normal" index is speeding this.
The clustered index cannot be sorted to satisfy all searches...
In case of having a clustered index the "normal" index for the other column holds the information/search item for searching then in clustered index.


No, you're never too old to Yak'n'Roll if you're too young to die.
Go to Top of Page

laddu
Constraint Violating Yak Guru

USA
331 Posts

Posted - 06/28/2009 :  03:32:41  Show Profile  Reply with Quote
Clustered index-->Reorders the way records in the table are physically stored. Therefore table can have only one clustered index.
The leafnodes of clustered index contain the data pages.
Table and index are same
Non- clustered index-->In which the logical order of the index does not match the physical stored order of the rows on disk
The leafnode of non clustered index does not consist of the data pages. Instead , the leaf nodes contain index rows.
Table and index are different from each other


Go through below link...hope it will help
http://www.sql-server-performance.com/tips/nonclustered_indexes_p1.aspx
Go to Top of Page

rajdaksha
Aged Yak Warrior

595 Posts

Posted - 06/29/2009 :  10:16:28  Show Profile  Send rajdaksha a Yahoo! Message  Reply with Quote
A clustered index determines the physical order of data in a table. A clustered index is analogous to a telephone directory, which arranges data by last name. Because the clustered index dictates the physical storage order of the data in the table, a table can contain only one clustered index. However, the index can comprise multiple columns (a composite index), like the way a telephone directory is organized by last name and first name.

by
raj...:)
Go to Top of Page

aakcse
Aged Yak Warrior

India
570 Posts

Posted - 07/09/2009 :  02:52:16  Show Profile  Reply with Quote
Thanks you for the reply, I got it... correct me If I am worng. there are only 3 types of allocation unit
1. In_row_data
2. Lob_data
3. Row_overflow_data

Any datatype (data rows) should fit into one of these there type of allocation unit.

Regards,
A
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
SQL Server Forums © 2000-2009 SQLTeam Publishing, LLC Go To Top Of Page
This page was generated in 0.08 seconds. Powered By: Snitz Forums 2000