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 setinstead 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:craig.russ...@sun.com P.S. A good JDO? O, Gasp!
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