Hi.

Could you show me (with code) how are you using the NHibernate? I'd like to know how do you manage SessionFactory, Sessions and etc.

I think this sould be a fixed topic (not this, but other clearer..) to tell the users what is the correct (or the best) way to use NHibernate.

My way:

Nowadays, I just keep a singleton pattern for SessionFactory. I have a GetSession method that every time returns a new Session.

Code:



Using this, I have to control the Transactrion and Sessions in the Interface Layer.

What are you using? Can you tell me? Thanks

Have you seen the NHibernate facility (an extension to the Windsor IOC container) available at http://www.castleproject.org/index.php/Main_Page

There is another interesting project built over NHibernate called ActiveRecord.
Check these out.....

Hi Samujob!

Are you talking about Castle.Facilities.NHibernateExtension ?

I believe Castle.Facilities.NHibernateExtension has been deprecated and replaced by Castle.Facilities.NHibernateIntegration. It has some nice features like automatic session management, automatic transaction handling.

I've also found this: http://www.castleproject.org/index.php/ ... NHibernate

Thanks.

Looks interesting, but it seems more awkward than the approach in .NET 2.0 with System.Transactions, using TransactionScope. With Castle.Facilities.NHibernateIntegration and Castle.Facilities.AutomaticTransactionManagement, apparently you need to make your methods virtual because your DAOs will be proxied. You need to mark your classes with the [Transactional] attribute, and define transaction boundaries on a per-method basis with [Transaction(TransactionMode.Whatever)]. I don't think System.Transactions has the same limitations.

In the example they give,

the session is implictly disposed. I'm confused -- I thought we wanted to not only be able to join an ambient transaction, but an ambient session. I.e. SessionManager.OpenSession() would return the ambient session if one exists, instead of a new one. If so, the ambient session would be disposed by this block of code! I'm confused -- how can a transaction live across multiple NHibernate sessions?

Hi there,

You can customize the NHibernateIntegration facility to suit your needs, by removing the Castle's Automatic Transaction Managemenet feature.

Instead, you can define your own transactional attributes to mark you business methods, intercept the business method calls of you business components (by placing your components in the Caste's Micro Kernel) and, in you interceptor, use the transaction management of the .net 2.0 System.Transactions namespace using the TransactionScope. :)

Concerning the SessionManager of the NHibernateIntegration facility, it returns you a wrapper of the ISession that is not actually disposed when the 'using block' ends, so you can use the same underlying ISession during a transaction lifetime.

Using a Generic DAO component that uses the SessionManager & an interceptor for your business components to take care of transaction management, you can have clean code in your business components (no session management / data access code, only calls to a generic DAO, and transactional attributes on your business classes / methods).

Stiiifff

Let me clarify few things regarding the NHibernate facility in Castle

Even when you are using the session in this manner:



the session will not be disposed if there is a CurrentTransaction in progress (see the Dispose implementation in SessionDelegate class).

Now the second point:
After a call to OpenSession on SessionManager any further call to OpenSession would return the same session. for e.g. if in MyDAO you get a session and call a method on MySecondDAO, the call to OpenSession in MySecondDAO will return the same Session.

Now regarding auto transaction:
As I said the transaction is not living across Sessions as the session is not disposed even when the Using block completes if there is a current transaction.
Whenever a transactional method calls another transactional method they share the same CurrentTransaction (this is achieved by the PerThread lifestyle of the NHibernateTransactionManager class) and the transaction gets committed or rolledback only when the root method finishes however the child transactios can vote for rollback.

Hope this helps....