Enthuware

Hi

I think the query

select s.courses from Student s

is correct, I test the same query on the toyAppForJPA

SELECT co.lineItems FROM CustOrder co

and get the results:

JPA Query Output -
[ArrayList Size=20
[OrderLineItem : salesapp.OrderLineItem[id=1 quantity=2 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=2 quantity=2 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=3 quantity=4 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=4 quantity=3 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=5 quantity=5 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=6 quantity=3 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=7 quantity=4 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=8 quantity=1 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=9 quantity=3 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=10 quantity=5 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=11 quantity=4 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=12 quantity=5 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=13 quantity=1 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=14 quantity=1 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=15 quantity=4 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=16 quantity=1 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=17 quantity=2 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=18 quantity=5 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=19 quantity=2 item = Not Loaded]]
[OrderLineItem : salesapp.OrderLineItem[id=20 quantity=3 item = Not Loaded]]
]


Can you explain why it is not a valid query?

Thanks,
Peter

I checked the specification seems it is correct, but please combine the last choice of enthuware.oce-jpad.v6.2.596

SELECT co.customer FROM CustOrder co

why it is correct?

does single-valued expression mean the returned associated entity must be at most one? but s.courses can have more that one?

Hi Peter,

When in doubt, use JPA 2.0 specification, not EclipseLink.

JPA 2.0 specification is a Bible for 1Z0-898.

Please, refer Section 4.8 SELECT Clause:

select_clause ::= SELECT [DISTINCT] select_item {, select_item}*
select_item ::= select_expression [ [AS] result_variable]
select_expression ::=
single_valued_path_expression |
scalar_expression |
aggregate_expression |
identification_variable |
OBJECT(identification_variable) |
constructor_expression

If you wish to select values from "collection valued path expression" (specification terminology), there are 2 options:

1) JOIN syntax:
2) IN syntax:
Best regards,
Mikalai Zaikin

OK, got it

Thanks,
Peter

In the explanation , it says "SELECT li from Order o IN (o.lineItems) li".
I think we need a comma, before the IN like this one:
SELECT li from Order o, IN (o.lineItems) li