HI everyone:

I want to know if "session.load" don't hit database? Is there any benefit to use session.load other than session.get ? thks!

session.load gives an exception if the object is not found, session.get returns null

Assuming you have a lazy (or proxied) domain object, session load will return the proxy (if its not cached) that may possibly represent a record that does not exist in the database. At times this is a great feature but it may be an issue in others. session.get always hits the database (if its not cached) thus you have a good idea if the record exists or not but at the cost of a database access. You need to decided which is appropriate for your use case.

David,

I converted from Hibernate v2.x to v3 and ran into problems with the session.load returning proxies when lazy is enabled. My workaround was to use Hibnernate.initialize( ...), so Exceptions are thrown when you would expect them (when using session.load). Is this a good / the right solution?

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Thanks,
Kristian

I think it is very dangrous! You mean that I may display a incorrect recordset to client? Is there any meaning to do this? It is certainly that the client want to see the record that is in the database,right? ;-(

Some people have not noticed (or read about) the change to lazy=true being the default in H3. You could call initialise to verify the objects existance though I feel its not the best approach as I do not like using exceptions to indicate anything other than a fault.
If you want to load the object and make sure that it is present then use session.get() which will return a null if the object did not exist at the time of the read transaction was performed.

Not quite sure what your concern is here. I agree you can display an stale record to the user. This is always a possibility in a multi-user system. Anyway, the proxy allows you to get a key reference without hiting the database. Yes the object with that key may not exist in the database so care is required. This is no different to you getting an object and that object gets deleted by another user just after your load. You have a object which does not exist in the database. An exception at some point will be thrown and you manage it appropriately. The developer is the best person to judge the ballance against db hit cost and life cycle of existing objects.

Kristian wrote:

David wrote:

I agree that it doesn't feel like the best approach. But as you say, exceptions should indicate a fault and there are many use cases where not getting the object indicates a fault. My impression is that the load method is for exactly this. Since it returns a proxy, we need some way of throwing an exception if the object doesn't exist. I'm probably misunderstanding something here, but for me it doesn't make any sense that the load method changes behavior depending on if you use lazy loading or not.

David wrote:

Yes, I use the get() method when this behavior is what I'm looking for. But as I mentioned above, there are cases when non-existence of the object indicates a fault and should result in an exception.

You could check for null and throw an exception accordingly. But this becames very tedious and repetitive.

Best regards,
Kristian