On 1/22/2013 11:04 AM, Oliver Gierke wrote:
> Okay, what's the reason to forbid that?
>
The orderby rules were written to allow direct mapping to SQL. If an implementation
were to support ordering by something that were incidentally fetched but not in the
SELECT list that would be one thing -- but I don't think we should require support for this.
> --
> Sent while on the run...
>
> Am 22.01.2013 um 19:34 schrieb Linda DeMichiel<linda.demichiel_at_oracle.com>:
>
>> Hi Oliver,
>>
>> On 1/20/2013 1:07 AM, Oliver Gierke wrote:
>>> Hi all,
>>>
>>> I have a user asking why a query he builds using a fetch clause gets rejected as soon as he's referring to the association declared in the fetch clause:
>>>
>>> @Entity
>>> class Person {
>>>
>>> @OneToOne Address address;
>>> }
>>>
>>> @Entity
>>> class Address {
>>> String city;
>>> }
>>>
>>> select p from Person p left join fetch p.address where p.firstname = :firstname
>>>
>>> works, whereas
>>>
>>> select p from Person p left join fetch p.address where p.firstname = :firstname order by p.address.city
>>>
>>> fails on Hibernate with the following error message:
>>>
>>> "query specified join fetching, but the owner of the fetched association was not present in the select list"
>>>
>>> This definitely makes some sense to me as Section 4.4.5.3 of the spec explicitly states:
>>>
>>>> The association referenced by the right side of the FETCH JOIN clause must be an association or element collection that is referenced from an entity or embeddable that is returned as a result of the query. It is not permitted to specify an identification variable for the objects referenced by the right side of the FETCH JOIN clause, and hence references to the implicitly fetched entities or elements *cannot appear elsewhere in the query.*
>>>
>>> I browsed the spec intensively but couldn't find any discussion of how to combine order by clauses with fetch joins as one obviously has to violate the latter of the two statements if one wants to sort by a property referenced in the fetch clause.
>>>
>>> What's the intended way of combining ORDER BY clauses and FETCH JOINs?
>>
>> I guess I don't understand your question. Are you asking how you can order query results by the target
>> of the join fetch? If so, the intent of the spec is that you can not do that.
>>
>> regards,
>>
>> -Linda
>>
>>
>>
>>> Cheers,
>>> Ollie
>>>