NOLOCK vs. Transaction Isolation Level

Question

What\'s the difference between using \"SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED\" and NOLOCK? Is one better than the other?

Answer 1

They have the same effect, only one is used as a lock hint (nolock) and the other is used for a connection scope.

Be careful with either of those - dirty reads can be a very bad thing depending on your app. Reading the same record twice or missing a record because of page movement can be a very confusing thing to users...