Another questions and my findings on using optional in subqueries:
1) Using Optional inside subqueries works just fine, as expected.
String singleStringJDOQL1 =
"SELECT FROM " + OptionalSample.class.getName() + "
WHERE " +
"(select max(a.id) from " +
OptionalSample.class.getName() + " a " +
"where a.optionalPC.isPresent() ) == id";
String singleStringJDOQL2 =
"SELECT FROM " + OptionalSample.class.getName() + "
WHERE " +
"(select max(a.id) from " +
OptionalSample.class.getName() + " a " +
"where a.optionalPC.get() != null) == id";
I will upload a modified test harness that checks this functionality.
2) Another question.
According to
https://docs.oracle.com/cd/E13189_01/kodo/docs324/ref_guide_subqueries.html
(last example), subqueries can return collections. I tried to to call
".isEmpty()" and ".get(0)" on them and I get (I hope I didn't screw up
my tests again):
"Cannot perform operation ".isEmpty" on
org.datanucleus.store.rdbms.sql.expression.SubqueryExpression"
"Cannot perform operation ".get" on
org.datanucleus.store.rdbms.sql.expression.SubqueryExpression"
Query example:
String singleStringJDOQL1 =
"SELECT FROM " + OptionalSample.class.getName() + "
WHERE " +
"(select from " + OptionalSample.class.getName() + " a " +
"where a.optionalPC != null).isEmpty()";
String singleStringJDOQL4 =
"SELECT FROM " + OptionalSample.class.getName() + " WHERE " +
"(select from " + OptionalSample.class.getName() + " a " +
"where a.optionalPC != null).get(0).optionalPC.isPresent()";
In the spec I couldn't find a definition of what subqueries should
return (examples in 14.10.18 and 14.10.19 return aggregates). So I
suppose they should be able to return collections?
It seems that the TCK tests for subqueries use exclusively aggregates,
so I'm not sure whether this is an omission or whether it is nor
supposed to be possible.
Below is a code snippet that can be simply plugged in into the
SupportedOptionalMethods.java test.
Cheers,
Tilmann
/**
* This methods tests that subqueries as collections.
*/
public void testSubqueriesNoOptional() {
//TODO
//this gives:
//Cannot perform operation ".isEmpty" on
org.datanucleus.store.rdbms.sql.expression.SubqueryExpression
//However, it should be possible according to:
//https://docs.oracle.com/cd/E13189_01/kodo/docs324/ref_guide_subqueries.html
String singleStringJDOQL1 =
"SELECT FROM " + OptionalSample.class.getName() + "
WHERE " +
"(select from " + OptionalSample.class.getName() + " a " +
"where a.optionalPC != null).isEmpty()";
Object[] expectedResult1 = new Object[]{oidReferencedPC1};
checkSingleStringQuery(singleStringJDOQL1, expectedResult1);
//TODO
//This gives:
//Cannot perform operation ".get" on
org.datanucleus.store.rdbms.sql.expression.SubqueryExpression
String singleStringJDOQL4 =
"SELECT FROM " + OptionalSample.class.getName() + " WHERE " +
"(select from " + OptionalSample.class.getName() + " a " +
"where a.optionalPC != null).get(0).optionalPC.isPresent()";
Object[] expectedResult4 = new Object[]{oidReferencedPC1};
checkSingleStringQuery(singleStringJDOQL4, expectedResult4);
}
On 24.09.2016 18:59, Tilmann wrote:
Thanks!
Looks like I made a mistake during results checks, it works now, sorry
for that.
Tilmann
On 24.09.2016 18:32, Craig Russell wrote:
The subselect would return 88 and then the outer select would become
"SELECT FROM " + OptionalSample.class.getName() + "
WHERE " +
“(88) == id”;
Seems to me this should select the object whose id is 88.
Craig
On Sep 24, 2016, at 9:22 AM, Tilmann <zaesc...@gmx.de> wrote:
Hi,
could I get some feedback?
I tried the following subquery:
"SELECT FROM " + OptionalSample.class.getName() + "
WHERE " +
"(select max(a.id) from " +
OptionalSample.class.getName() + " a " +
"where a.optionalPC != null) == id";
This returns '88' (an integer) instead of the object with id==88. Is
this expected to return an integer?
Full code (can be used in SupportedOptionalMethods.java):
String singleStringJDOQL2 =
"SELECT FROM " + OptionalSample.class.getName() + "
WHERE " +
"(select max(a.id) from " +
OptionalSample.class.getName() + " a " +
"where a.optionalPC != null) == id";
Object[] expectedResult2 = new Object[]{oidReferencedPC1};
// single String JDOQL
Query singleStringQuery2 = pm.newQuery(singleStringJDOQL2);
executeJDOQuery(ASSERTION_FAILED, singleStringQuery2,
singleStringJDOQL2,
false, null, expectedResult2, true);
Kind regards,
Tilmann
