Small clarification regarding modify and save method

Hi Experts ,

Needed a small clarification  ...

When we do a bol core MODIFY ( lr_core->modify( ) )  the data from the bol buffer is put in the transactional buffer , now in order to save this data we create an instance of the transaction context and save the changes , now my query here is when we are saving the data we create an instance of transactional context for a particular entity (say BTORDER)  , then is it that data for only BTORDER will be saved from the buffer into the database and the data for  other objects will still be there in the transactional buffer .

Please suggest .

Thanks ,

Vaibhav