Re: Is INNER JOIN necessary with ORDER BY?

[Craig L Russell]

Hi Ognjen,






Regards,

Craig

On Mar 26, 2008, at 5:14 AM, Ognjen Blagojevic wrote:

As I understand the JPA specification, your analysis and solution are correct. By the specification, navigating a relationship uses inner join semantics. By the way, JDO uses outer join semantics in query navigation. With JDO, you would get Persons with null id_place_of_birth unless your query explicitly had a query clause id_place_of_birth != null. Of course, the position of the null entries in the result list still might be before or after non-null entries.

Hi all,



For instance, EJB QL

 select p
   from Person p
  order by p.idPlaceOfBirth.name



The only solution I found so far is to explicitly use

 select p
   from Person LEFT OUTER JOIN p.idPlaceOfBirth b
  order by p.idPlaceOfBirth.name

But it tends to unnecessarily add to the EJB QL queries complexity.

Is there any other way to do the same thing?

Regards,
Ognjen

How can I avoid INNER JOINs to be generated for tables stated in ORDER BY clause? results in SQL which INNER JOINS Person and Place, and the persons without known place of birth (id_place_of_birth == null), are not listed.

Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!

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