[jboss-user] [Persistence, JBoss/CMP, Hibernate, Database] - Hibernate query not smart!

mimmo67 do-not-reply at jboss.com
Thu Feb 19 09:26:49 EST 2009


Hi all.
I have a query automatically generate by Hibernate derived from different classes often mapped on the same Oracle table.
The problem is that I obtain something like this:

select * from A action0_ 
    left outer join
        B action0_1_ 
            on action0_.TRANS_ID=action0_1_.TRANS_ID 
    left outer join
        C action0_2_ 
            on action0_.TRANS_ID=action0_2_.TRANS_ID 
    left outer join
        C action0_3_ 
            on action0_.TRANS_ID=action0_3_.TRANS_ID 
    left outer join
        C action0_4_ 
            on action0_.TRANS_ID=action0_4_.TRANS_ID     where
.........

The same table is outer joined 3 times. This drammatically reduce the query performance.
There is a way to indicate to Hibernate to generate better queries where different classes use the same Oracle tables or I have to work only on the mapping to avoid situation like this?
Thank you.
Best regards from Italy,
Domenico

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