I'm afraid my question is very specific to Sybase and not of interest to others. In my organization the database administrators are complaining, that Hibernate makes a lot of hits to the database asking whether the transaction mode used is chained or unchained.

This web site explains the concepts of chained and unchained:
http://snmgeeks.blogspot.com/2007/06/sybase-facts-about-transactions.html

Chained: - Each data retrieval or modification statement is preceded by a begin tran.
All nested transactions can only be started in by an explicit begin tran.

Unchained: - (Default) an explicit begin tran must be given to start a transaction.

The DBAs are asking, if there is a way to tell to Hibernate once the transaction mode and then Hibernate wouldn't have to ask it continuously. I have googled but haven't found anything.