I'm trying to get Apache Roller working with JPA and I've had some
success (thanks to Sun's Craig Russell and Mitesh Meswani) -- I was
able to get 100% of the Roller unit tests working with OpenJPA and
Toplink/JPA and running against Derby and MySQL.
However, I'd like to be able to use sub-selects and thus far that's
been impossible with OpenJPA. Problem is, if I turn on sub-select
support via SupportsSubselect=true, OpenJPA starts using sub-selects
all over the place -- in places where I didn't code a sub-select --
and I start getting exceptions like this:
<0|false|0.9.6-incubating>
org.apache.openjpa.persistence.PersistenceException: You can't specify
target table 'roller_weblogentrytagagg' for upd
ate in FROM clause {prepstmnt 9396085 DELETE FROM
roller_weblogentrytagagg WHERE id IN (SELECT DISTINCT t0.id FROM
roller_weblogentrytagagg t0 WH
ERE (t0.websiteid = ?)) [params=(String)
befd0c00-757c-4aef-b926-008d7d0696cb]} [code=1093, state=HY000]
FailedObject: [EMAIL PROTECTED]
at
org.apache.openjpa.jdbc.sql.DBDictionary.newStoreException(DBDictionary.java:3720)
NestedThrowables:
java.sql.SQLException: You can't specify target table
'roller_tasklock' for update in FROM clause
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2975)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1600)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1695)
at com.mysql.jdbc.Connection.execSQL(Connection.java:3026)
Apparently referencing the update target table in a from-clause
sub-select is not permitted by MySQL. I'm not sure why OpenJPA feels
the need to use sub-selects in updates; it's unnecessary and
problematic. So my question is this: is there some way to keep OpenJPA
from using sub-selects in update queries?
- Dave
