sql server isoloation levels

[Josh Golden]

how do I know what sql server isoloation level to use? i don't think i
should post this in the sql group because my question is for developing in
dot net vb. is anyone in this group setting isolation levels in their code?
if so what level are you using?

 

[Mary Chipman]

The default isolation level is read committed, which ensures that you
only see data that is actually in the database (no dirty reads). This
is usually fine for most purposes. More restrictive isolation levels
can cause blocking and deadlocks, and should be avoided. If you need
to compute complex aggregate against a large dataset where you don't
care about the values in individual rows, create a stored procedure
where you can use the read uncommitted isolation level. Setting the
isolation level on the client sets it for the whole connection until
it is changed, whereas setting it in a stored procedure sets it only
for the duration of the stored procedure. For more info, see the
isolation level topics in SQL BooksOnline.

--Mary