Hi Craig,

I'm not so sure whether this is really what you want to see, but here's something:
Query query = newQuery("new Date()");
query.setResultClass(java.sql.Timestamp.class);
query.setUnique(true);
Date result = (Date)timeQuery.execute();
  
That result Date can then be used to e.g. set an updated object's lastModification timestamp before committing it.

Regards,
Jörg

Craig L Russell schrieb:
Hi Jörg,

Sorry to exercise you more on this, but I'm still having a bit of difficulty seeing how to use this feature.

Could you please give us an example of the use case you describe below? I'd like to see the JDOQL query that uses new Date() in action.

Thanks!

Craig

On Oct 19, 2006, at 1:33 AM, Jörg von Frantzius wrote:

Hello Craig,

as far as I can see that does satisfy our requirements. Once we are able to query for that date in JDOQL, we can use it e.g. for lastmodification timestamps and the like.

Regards,
Jörg

Craig L Russell schrieb:
It's easy enough to define "new Date()" as being evaluated on the back end for queries that are executed on the back end. And being evaluated in the vm for queries that have a bound candidateCollection.

But does this satisfy the requirements? Once you have a Date in JDOQL, what can you do with it?

Craig

On Oct 16, 2006, at 11:58 AM, Erik Bengtson wrote:

+1. maybe "new Date()" could be the expression where evaluation occurs on the
database.

Quoting Jörg von Frantzius <joerg.von.frantzius@artnology.com>:

Dear experts,

there had been several occasions where in our applications we had to
determine the database server's current time(-stamp). In one application
we needed it to synchronize sent JMS messages with visibility of commits
in the database, and in another we need it for our simple replication
algorithm.

In distributed systems in general it is often crucial for
synchronization purposes to have a common source of time information
that is accessible from all processes.

It would be great if JDO2 could offer a way of doing that independently
of the database, e.g. as a JDOQL function.


Regards,
Jörg





Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:Craig.Russell@sun.com
P.S. A good JDO? O, Gasp!



Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:Craig.Russell@sun.com
P.S. A good JDO? O, Gasp!