I would expect that your query would return the unfiltered employees collection. But I have not run any tests.
In other words, I would expect that the oldtimers collection would be the full set of employees for each dept that had any oldtimers >= 15. That said, I don't think that your interpretation is necessarily wrong. Just not my expectation. -Patrick -- Patrick Linskey BEA Systems, Inc. _______________________________________________________________________ Notice: This email message, together with any attachments, may contain information of BEA Systems, Inc., its subsidiaries and affiliated entities, that may be confidential, proprietary, copyrighted and/or legally privileged, and is intended solely for the use of the individual or entity named in this message. If you are not the intended recipient, and have received this message in error, please immediately return this by email and then delete it. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Sent: Friday, February 23, 2007 4:14 PM > To: open-jpa-dev@incubator.apache.org > Subject: Re: possible to write a JPA Query to that filters > both an Entity and its relationship entities? > > Hi Patrick, > > From the JPQL > select dept, oldtimers from Department dept LEFT JOIN > dept.employeeCollection oldtimers WHERE dept.deptno >= 100 AND > oldtimers.yearsOfService >= 15 > > I expect to get SQL that looks something like > select dept.id, dept.name, oldtimers.id, oldtimers.firstname, > oldtimers.lastname, oldtimers.salary, oldtimers.ssn from Department > dept, Employee oldtimers WHERE dept.id = oldtimers.deptid AND > dept.deptno >= 100 AND oldtimers.yearsOfService >= 15 > > I then construct instances from the returned dept and oldtimers > columns and give back to the user the results, with one result row > for each SQL ResultSet row. So the filtering from the JPQL > translated > into the WHERE clause in the SQL should exclude oldtimers that don't > qualify. > > If you don't use the oldtimers.yearsOfService >= 15 in the SQL, then > you will get all of the employees in the department returned in the > result. But why do you not use the oldtimers.yearsOfService >= 15 in > the SQL? > > Craig > > On Feb 23, 2007, at 2:12 PM, Patrick Linskey wrote: > > >> In fact, you have to do a bit of work to get SQL to return you non- > >> filtered instances. So I don't get it. Does OpenJPA not > >> construct the > >> obvious SQL that filters oldtimers? > > > > I don't think that you and I are really in sync here. Maybe > some more > > concrete examples are in order? > > > > -Patrick > > > > -- > > Patrick Linskey > > BEA Systems, Inc. > > > > > ______________________________________________________________ > ________ > > _ > > Notice: This email message, together with any attachments, may > > contain > > information of BEA Systems, Inc., its subsidiaries and > > affiliated > > entities, that may be confidential, proprietary, copyrighted > > and/or > > legally privileged, and is intended solely for the use of the > > individual > > or entity named in this message. If you are not the intended > > recipient, > > and have received this message in error, please immediately return > > this > > by email and then delete it. > > > >> -----Original Message----- > >> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > >> Sent: Friday, February 23, 2007 2:09 PM > >> To: open-jpa-dev@incubator.apache.org > >> Subject: Re: possible to write a JPA Query to that filters > >> both an Entity and its relationship entities? > >> > >> So, > >> > >> I can tell you that having a result column that is filtered in the > >> query is not what a user would expect. In JDO, the oldtimers column > >> would be filtered. > >> > >> In fact, you have to do a bit of work to get SQL to return you non- > >> filtered instances. So I don't get it. Does OpenJPA not > >> construct the > >> obvious SQL that filters oldtimers? > >> > >> I've re-read the JPA specification, and it appears to be silent on > >> the issue of filtering. Is this a portability issue? > >> > >> Craig > >> > >> On Feb 23, 2007, at 1:57 PM, Tom Mutdosch wrote: > >> > >>> Hi Patrick, > >>> Thanks for the query suggestion. I guess what I was initially > >>> thinking of doing was incorrect in that JPA doesn't really give me > >>> a "view" of what I want. That is, I can never get a Department > >>> object containing a list of filtered Employees. A JPA object > >>> returned from a query is always going to be an exact > >> representation > >>> of the database. So your Department object is always going to > >>> contain all of the Employees in its relationship. > >>> > >>> So like you mentioned, I can still get all the information using > >>> one query, and then just process those results as I want them. I > >>> imagine that this would entail some sort of wrapper bean > >> that would > >>> house the Department and the filtered list of Employees. Or what > >>> if I added a regular method to my Department entity called > >>> getFilterEmployees() which would return a List that I populated > >>> with the filtered results from my query? Does that seem like a > >>> reasonable thing to do -- if I didn't want to deal with a wrapper > >>> object but still have all of my desired data captured by a single > >>> Entity? > >>> Thanks > >>> Tom > >>> > >>> > >>> Patrick Linskey wrote: > >>>> It is, but it doesn't buy you much in this situation -- > >> the oldTimers > >>>> collection in your example won't be filtered to just the > >> ones that > >>>> are > >>>> old. It'll be all the employees in the dept. > >>>> > >>>> -Patrick > >>>> > >>>> > >> > >> 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! > >> > >> > > 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! > >
