hi all,
i m a beginner with Hibernate and i want to ask few questions about how can i use it in a J2EE app.
I have implemented a 'PersistenceManager' layer in my app, which is in charge of interacting with the database.
My app is a struts-based app, so i have downloaded the hibernate plugin for struts which instantiates a SessionFactory.
question 1: do i have to open/close/refresh a transaction every time my persistence manager has to do some operation (insert/delete/update)?
question 2: do i have to start and commit a transaction every time i want to do an insert/update/delete?

thanx in advance and regards
marco

hi,
i've tried struts plug in and threadlocal session, i prefer threadlocal.... you should take a look.

Your questions are related to transaction management.
Hibernate does not have "specific" transaction management so just use it as if you were working in jdbc.
I think the most important is to understand "flush", for this reaf the reference doc, it is well explained
And last advices:
1- consider hibernate session as a business process cache
2- hibernate session is not a "global" cache (second level cache)
3- Hibernate session is not threadsafe, using threadlocal session help you to prevent big errors
4- in a web app, the best practice is one hibernate session per hhtp request, in you need other way, you can do it but you must know what you are doing


Anthony

Hi Anthony,
thanx for the advice.... i have one more question on transactions..
reason of why i have asked is that in some examples, when creating an object, the code is 'wrapped' in a transaction, while in other cases there is no transaction at all...
so, from your reply i assume following code is perfectly valid (meaning, there is no transaction code at all..)

ThreadLocal session = new ThreadLocal90

SessionFactory sf = (SessionFactory) new InitialContext().lookup("SessionFactory");

Session s = sf.openSession();
session.set(s);

Test myclass = new Test();
mclass.setDescription("foobar");

session.save(myclass);


regards
marc

with your code, your changes will simply not be persisted

this code


does not need transaction because it's only an "initialisation"

now, the second part of code should be

Hi anthony,
ok i got the answer myself by reading docs... whenever i create an object i have to do it within a transaction..

thanx 4 ur help anyway and regards
marco

even for a simple select you must use a transaction = best practice