OK, I'll digg that way, it sound very interesting !
I hope fetch group can be assigned dynamically, if yes, as far as I
understood it, it will beautifully solve my problem.
On Jul 28, 2009, at 23:08 , Craig L Russell wrote:
Hi,
If what you want is the result as an A with some number of fields
populated, you can use a fetch plan with a fetch group that calls
for just the fields that you need.
In my experience, there is not much performance difference between
fetching 1 primitive field versus 10 primitive fields from the
database. If you fetch 100 or 1000, there might be a difference.
Craig
On Jul 28, 2009, at 1:08 PM, Jean-Baptiste BRIAUD -- Novlog wrote:
OK, that will solve from 40 to 60% of my problem :-)
In fact, if I understood correctly, this need a specific constructor.
When request is static, it solve the problem.
But when the request is dynamic (the request's string provided at
runtime) I can't provide the corresponding constructor at runtime.
Any idea for that cases ?
Related question : does it save a lot of time and ressources to
restrict attribute retreived from database ?
In fact, one solution might be to always retreive all
attributes ... but I always learn from plain old SQL to use the
select part of the SQL request to restrict as much as possible the
columns to retreive.
Any ideas welcome !
On Jul 28, 2009, at 20:37 , Luis Fernando Planella Gonzalez wrote:
Use select new A(a.attribute1, a.attribute2) from A a
Create a constructor to accommodate the received parameters.
Em Terça-feira 28 Julho 2009, às 15:27:31, Jean-Baptiste BRIAUD --
Novlog escreveu:
Hi,
If I use the following request SELECT a FROM A a, I got a List<A>
witch is perfectly fine.
If I use SELECT a.attribute1, a.attribute2 FROM A a, I got a
List<Object[]> where each List element is an array of 2 values for
attribute1 and attribute2.
How can I have a List<A> where only attribute1 and attribute2 are
set
instead of that List<Object[]> ?
Thanks.
PS : I sent this message 3 hours ago but can't see it on the
list...
so I decided to write this one.
Craig L Russell
Architect, Sun Java Enterprise System http://db.apache.org/jdo
408 276-5638 mailto:[email protected]
P.S. A good JDO? O, Gasp!
