.NET Tutorials, Forums, Interview Questions And Answers
Welcome :Guest
Sign In
Win Surprise Gifts!!!

Top 5 Contributors of the Month
david stephan
Gaurav Pal

Home >> Interview Question >> Sql Server >> Post New Question Subscribe to Interview Questions

Why NoLock is used in Sql Select Query?

Posted By :Rajshree     Posted Date :September 16, 2010    Points :10   Category :Sql Server 
applying nolock in select statement will increase
concurreny and performance in fetching.

it does'nt consider the transaction scenario, even if the
transaction is under process not yet commited or rollback
it will fetch the current record

begin tran
insert into tablename

select * from tablename with (nolock)

-- it will display the table with inserted record.
but the transaction is not completed, it can be rollback
so it became dirty read.

You can also find related Interview Question to Why NoLock is used in Sql Select Query?  below: 

Write a query to Select top 2 Highest salaries?

select Top(2) salary from Tablename order by Salary desc.... (More...)

Would the select query below fetch any records?

create table #testvm (ID int)

select * from sysobjects where name = '#testvm'

drop table #testvm


Since temp tables are created in tempdb, and use a random name, the query will not work.

If you used a query like this, you would see your table:

select * from tempdb..sysobjects where name like '#testvm%' (More...)

What is Query evaluation engine?

It executes low-level instruction generated by compiler. (More...)

What is Query binding ?

The binding of an object to a query (More...)

Select Syntax


Write and justify output of - select nullif('test','test')

The output will be - NULL
Justification : nullif returns NULl if given two arguments are same else returns the first specified argument. So, for the given SQL, output will be NULL. (More...)

Quick Links For Interview Questions Categories:
ASP.Net Windows Application   .NET Framework   C#   VB.Net   ADO.Net  
Sql Server   SharePoint   Silverlight   OOPs   JQuery   JavaScript/VBScript
Biztalk Patten/Practices .IIS WCF WPF WWF
Networking Aptitude Others   All      

Find questions, FAQ's and their answers related to .NET, C#, Vb.Net, Sql Server and many more.

Now you can find lots of .NET, C#, Vb.Net, SQL Server,Windows, ASP.Net related Questions and their Answers here at www.dotnetspark.com. Our aim is to help you pass your certification Exams (MCP, MCSD, MCAD etc.,) with flying scores and get good name in your company.

So, Start looking our Interview Question section daily and improve your .NET Skills. You can also help others by posting Interview Questions and their Answers in this section.

Hall of Fame    Twitter   Terms of Service    Privacy Policy    Contact Us    Archives   Tell A Friend