Transactional integrity Sharepoint List

According to this, SharePoint 2010 does not offer any transactional support out of the box.

The underlying database does support transactions, so a single insert will probably either succeed or fail, but if an error occurs during a complex routine involving multiple database operations, the data will end up being partially modified.

Underneath the covers a single SharePoint operation like adding a list item can involve multiple database operations and they will all be protected by a single database transaction. With that said, the product doesn't expose that transactional capability to you so that you can perform multiple SharePoint operations under the aegis of a single transaction. To be very safe, you'll need to implement very carefully coded error handlers.

Sharepoint does not offer transaction support out of the box.

Here is a good resource on Building a System.Transactions resource manager for SharePoint

Though I would save the effort and store any critical data directly into a RDB