[Re-post] PB query question

[Phil Warrick]

Hi again,

I posted this a few weeks ago, perhaps when the best person to answer
wasn't around (Jakob?).  Your suggestions would be welcome.
Here is my model:

[A] <1--n> [B] <1--n> [C] <1--1> [D]
                        | |
                       C1 C2
I want to query for A objects using a C1 timestamp field as criteria (C1
is a subclass of C and C does not have the timestamp field) and a D
string field as criteria.
If the timestamp field belonged to the C class, then there would be no
problem directly querying for A's.
Since the criteria is a C1 attribute I don't think that I can directly
query for A's, so I can do it in two steps by first querying for C1
objects and then iterating through the returned collection to gather the
A objects, as follows
// snippit begin
Criteria criteria1 = new Criteria();
Criteria criteria2 = new Criteria();
criteria1.addEqualTo("d.stringField", new String("foo"));
criteria2.addEqualTo("d.stringField", new String("foofoo"));
criteria1.addOrCriteria(criteria2);
                        
Criteria criteria3 = new Criteria();
criteria3.addBetween("timeStamp", timeStamp1, timeStamp2);
                        
criteria1.addAndCriteria(criteria3);
Query query = new QueryByCriteria(C1.class, criteria1);
Collection c1Set = broker.getCollectionByQuery(query);
java.util.Iterator itr = c1Set.iterator();
List aList = new ArrayList();
while (itr.hasNext())
{
     // gather the A's (more db hits here)
     A a = c1.getB().getA();
     aList.add(a);
}
// snippit end
It would be nice to reduce the DB hits and query for the A's directly as
is possible in with standard OQL:
select c1.b.a from c1 in C1.class
        where (c1.d.stringField = \"foo\" or
                 c1.d.stringField = \"foofoo\") and
        e.theTimestamp >= timestamp '" + timeStamp1 + "' " and
          e.theTimestamp <= timestamp '" + timeStamp2 + "' "
Is there any possibility that this is possible with PB queries?

Thanks for read this far,

Phil



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