I would like to manage transaction explicitly in the application (using JDBC). I believe it is possible, isnt'it?
If I understand correctly I must update the configuration setting autocommit on off. Can you tell me how can I set this configuration autocommit off? I believe this setting is established when the database is created, isnt'it?
And the second question is the following:
Can I use the sentence SAVE TRANSACTION? If not can you show me a similar sentence, please.
Thanks in advanced.

First of all, I would suggest that you read a book on JDBC. It should explain a lot of things to you and answer questions.

Now to answer your question.

KDBC has a Connection Class. It has to methods that you need:
setAutoCommit(boolean) and
commit().

1) Use SetAutoCommit(false) to "Start a transaction"
2) Use commit(). to "end the transaction" (you can setAutoCommit(true) optionally. If you do not, then your next transaction will start automatically after the commit()--you will not have to do step (1) again).

HTH

Andy