Crystal Reports with SQL Server 2005: Setting Transaction Isolation Level

Is there a way to specify the transaction isolation level when Crystal Reports queries a SQL Server 2005 database without resorting to any of the following:

• Encapsulating the report's query in a stored procedure that executes SET TRANSACTION ISOLATION LEVEL... before the query itself
• Han开发者_如何学Pythond-writing the SQL query in Crystal Reports to execute SET TRANSACTION ISOLATION LEVEL...

I was able to embed this in a Command object:

SET TRANSACTION ISOLATION LEVEL REPEATABLE READ

--Command objects need to return a value
SELECT GetDate()

This Command object was in addition to the query that I 'wrote' in the Database Expert.

Will you elaborate on the necessity of setting the ISOLATION LEVEL?