NOLOCK in SQL

Question

Hi Friends What is a NOLOCK in SQL ?

Neha Sharma · Answer

Hii Refer this link: http://www.allinterview.com/showanswers/5546.html if it helps you mark it as answer.

Satyapriya Nayak · Answer

http://www.devasp.net/net/articles/display/926.html

Santhosh Kumar Jayaraman · Answer

WITH (NOLOCK) is the equivalent of using READ UNCOMMITED as a transaction isolation level. So you stand the risk of reading an uncommitted row that is subsequently rolled back i.e. data never made it into the database. So while it can prevent reads being deadlocked by other operations. SELECT * FROM Employee WITH (READUNCOMMITTED) this is same as SELECT * FROM Employee WITH NOLOCK The NOLOCK and READUNCOMMITED hints are only allowed with SELECT statements. If we try to use this for an UPDATE DELETE or INSERT we will get an error. Check this link for an example. http://www.mssqltips.com/sqlservertip/2470/understanding-the-sql-server-nolock-hint/[^]