Golgappa.net | Golgappa.org | BagIndia.net | BodyIndia.Com | CabIndia.net | CarsBikes.net | CarsBikes.org | CashIndia.net | ConsumerIndia.net | CookingIndia.net | DataIndia.net | DealIndia.net | EmailIndia.net | FirstTablet.com | FirstTourist.com | ForsaleIndia.net | IndiaBody.Com | IndiaCab.net | IndiaCash.net | IndiaModel.net | KidForum.net | OfficeIndia.net | PaysIndia.com | RestaurantIndia.net | RestaurantsIndia.net | SaleForum.net | SellForum.net | SoldIndia.com | StarIndia.net | TomatoCab.com | TomatoCabs.com | TownIndia.com
Interested to Buy Any Domain ? << Click Here >> for more details...

  1. Categories >> Software >> Databases >> SQL Server
  2. Suggest New Category

What are statistics, under what circumstances they go out
of date, how do you update them?

Question Posted / swapna

Answers were Sorted based on User's Feedback



What are statistics, under what circumstances they go out of date, how do you update them?..

Answer / swapna

Statistics determine the selectivity of the indexes. If an
indexed column has unique values then the selectivity of
that index is more, as opposed to an index with non-unique
values. Query optimizer uses these indexes in determining
whether to choose an index or not while executing a query.

Some situations under which you should update statistics:
1) If there is significant change in the key values in the
index
2) If a large amount of data in an indexed column has been
added, changed, or removed (that is, if the distribution of
key values has changed), or the table has been truncated
using the TRUNCATE TABLE statement and then repopulated
3) Database is upgraded from a previous version

Is This Answer Correct ?    9 Yes 0 No

What are statistics, under what circumstances they go out of date, how do you update them?..

Answer / koti

Statistics determine the selectivity of the indexes. If an
indexed column has unique values then the selectivity of
that index is more . Query optimizer uses these statistics
in determining whether to choose an index or not while
executing a query.

To update statistics there is command :

update_statistics

Is This Answer Correct ?    1 Yes 3 No

Post New Answer

More SQL Server Interview Questions

What is temporary table in sql server? Why we use temp table?

0 Answers  

Do you know what are the properties of the relational tables?

0 Answers  

Can we call stored procedure in view in sql server?

0 Answers  

what are file groups?

3 Answers   Evalueserve,

What are types of storage modes? : sql server analysis services, ssas

0 Answers  

How to achieve Paging of records in SQL SERVER?

0 Answers   Petranics Solutions,

How to run sql server 2005 books online on your local system?

0 Answers  

What is a trace frag?

0 Answers  

i have 4 tables.. T1, T2, T3, T4.. these tables have the same structure and they store the information entered in different years.. T1 stored 2002, T2 stored 2003, T3 stored 2004 and T4 stored 2005.. i want to copy contents in T1 to T2, T2 to T3, T3 to T4 and T4 to T1.. how do i do that? Temp tables cannot be used..

4 Answers  

How can you check the level of fragmentation on a table?

0 Answers  

What is 2nf normalization form?

0 Answers  

default databases available in sql server and there uses ?

4 Answers   TCS,

For more SQL Server Interview Questions Click Here
Categories