in HIbernate 2.1, i use session.delete(String query) to do a mass deletion. When upgrade to 3.0, I found that function is gone. 3.0 only has session.delete(Object object). Does it mean I have to delete records one by one? No mass update on 3.0 or there is a better way to do mass deletion in 3.0?

Thanks in advance!

H2 that method was not a real builk update as it did it one by one based on the IDs collected.

H3 added Query.executeUpdate() for true bulk updates and delete.

Now you could use the classic API which the session is under org.hibernate.classic but the methods are deprecated.

That's all well and good, but what is the HQL syntax for a delete? It isn't documented anywhere.

Okay, after some trial and error I think I've figured it out. Pretty straight forward:

Well after all that it just changed :)

You can actuall no longer use aliases with update or delete statements in HQL. The syntax is actually:
delete [from] ClassName where propName = ?
(notice no aliases).

This is now in CVS and will be in the 3.0 final release

Steve, could you please explain the rationale behind the decision to remove aliases from HQL updates.

Not that I have a strong opinion against it, but, without having spent nights awake thinking about it, it seems that:

1) it would complicate/prevent joins in the update statement. If not, could you please provide an example to the contrary?

2) it deviates from both its native SQL counterpart and HQL selects, respectively.

Also, I use a composite PK class for an entity and couldn't use it in my statement as:

"update <EntityName> set <bla-bla-bla> where <compositePKClassInstanceName.attribute = :someValue".

Using the PK class attribute directly on the entity class however as follows:

"update <EntityName> set <bla-bla-bla> where attribute = :someValue".

, it worked.

This seems a bit unintuitive and non-consequential with respect to HQL selects. If working as designed, please explain the design decision.

Sincerely

/Par

Well, thats the whole point actually. Not all databases support joins (nor even aliased tables even) in UPDATE/DELETE statements.


Huh? Very few databases actually allow joins in UPDATE or DELETE statements. And a good many complain if you even attempt to alias the table in a UPDATE or DELETE statement, as I mentioned above.


Well, if true, that would be a bug.

Ok, I didn't know that. So if I really wanted to do a batch update with a join in Hibernate with a database that supports it, I guess I'm out of luck, since Hibernate does not support native SQL for update queries...? Perhaps not a big deal but good to know the options before resorting to JDBC or trying to code a workaround...

Also, I'll try to submit a formal bug report for the composite key example.

Thanks

/Par

Hi All,
I am not sure if iam helping in any way. but this is what I have noticed....

I could get a query string from the criterion.. This query string references the properties with its alias. Now if I use this to build the where condition for my query for deletion, I end up having the where clause having the alias where in the from clause is without the alias. I was wondering if there is a way of using the criteria for making dynamic queries.. I am trying this way of achieving this because there is a lot of idea/code reuse here and i would not want to reinvent what hibernate is already doing... (except for the little glitch ;) )

warm regards
Kiran