Incorrectly read attributes with custom SQL query

Question

Hi folks,
I'm trying to read in a random sampling of records from a table, so I tried:
ReadAllQuery q = new ReadAllQuery();
q.setReferenceClass(Foo.class);
q.addPartialAttribute("bar");
q.setSQLString("select * from Foo sample(10)");
q.useCursoredStream(100,100, new ValueReadQuery("select count(*) from Foo sample(10)"));
This all worked fine, the Foos were retrieved, but after the first dozen or so, all the "bar" attributes were null, which they should not be. This only occurs when using a custom SQL string. I tried bringing back all the objects (i.e., without using setSQLString) and examining them and all the "bar"s were present. But when I use setSQLString the attributes don't get read correctly.
Can anyone tell me what I'm doing wrong? Is there a better way to do it?
Thanks,
Bryn

Answer 1

Okay, here's the actual code:
ReadAllQuery q = new ReadAllQuery();
q.setReferenceClass(ActivityCenter.class);
boolean useCustom = true;
if (useCustom) {
q.setSQLString("SELECT SetupDt, TerminationDt, ReinstateDt, IID, upDt, ID, " +
"Stat, SubType, Acct FROM ACtr");
q.useCursoredStream(100,100, new ValueReadQuery("select count(IID) from actr"));
} else {
q.useCursoredStream(100,100);
session.logMessages();
activityCenters = (CursoredStream) session.executeQuery(q);
ActivityCenter ac = (ActivityCenter) activityCenters.read();
if (ac.getAccount() == null) {
System.err.println(ac.getID() + ": Oops!");
} else {
System.err.println(ac.getID() + ": Has account!");
System.exit(0);
So, everything about this program is the same - how the mapping is done, how things get initialized, everything. The only difference is whether I use a custom SQL query or not. Here's what it looks like when I run it both ways:
First, custom:
DatabaseSession(2433702)--Connection(393272)--SELECT SetupDt, TerminationDt, ReinstateDt, IID, upDt, ID, Stat, SubType, Acct FROM ACtr
1.1: Oops!
Now, without the custom SQL:
DatabaseSession(393272)--Connection(7896086)--SELECT SetupDt, TerminationDt, ReinstateDt, IID, upDt, ID, Stat, SubType, Acct FROM ACtr
DatabaseSession(393272)--Connection(7896086)--SELECT
//bunch of fields from the Acct attribute...
FROM Acct WHERE (IID= 'ffbe5c47f3ea762cfd50fbe9e6d6de6')
1.1: Has account!
Notice that the first query on Actr is identical in both cases. Also note there are no null Actr.acct fields in the database:
SQL> select * from actr where actr.acct is null;
no rows selected
SQL>
This is on Oracle 9i, with the thin jdbc driver.
Also, I was curious that you asked if I was using partial attributes - when I try to add a partial attribute when using the custom SQL string, I get exceptions like this one:
java.lang.ClassCastException: oracle.toplink.internal.queryframework.CallQueryMechanism
at oracle.toplink.queryframework.ObjectLevelReadQuery.initializeDefaultBuilder(Unknown Source)
at oracle.toplink.queryframework.ObjectLevelReadQuery.getExpressionBuilder(Unknown Source)
at oracle.toplink.queryframework.ObjectLevelReadQuery.addPartialAttribute(Unknown Source)
at jenkon.magellan.util.MLMulator.getActivityCenters(MLMulator.java:782)
at jenkon.magellan.util.MLMulator.run(MLMulator.java:897)
at jenkon.magellan.util.MLMulator.main(MLMulator.java:943)
Thanks,
Bryn