COM+ Transactions

Appologies if this is a really stupid question!

I am writting a component which runs under a COM+ transaction. What I would like to know is if I have a method which follows this flow:

1. Get details from Database
2. Generate report file
3. Email report
4. Update database

If an error occurs some where in the above steps, for example at step 4, is everything rolled back, i.e. will the e-mail still be sent even though the database isnt updated. If this is the case what do I need to do to ensure that either all the steps happen or none?

Thanks for your help