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Hibernate version: 2.1

Name and version of the database you are using:

I have 5 tables one parent table A, children tables: B, C, D, E. I used discreminator in the class A to distingusih the actual type of the data (child B, C, D or E). However, when I make a hql query, I found there are 4 sql generated every row I retrieved.

For example:

hql:

from A as a where A.type = 'B'


sql gerneated:

select * top 20 from A a, B b where (a.id=b.id )

select * from B where b.id = ?
select * from C where c.id = ?
select * from D where d.id = ?
select * from E where e.id = ?


As above example, there will be 80 sql generated to retrieve 20 recrods.

The performance of the query is extremely bad and I would like to know if it is possible in hibernate to execute 1 sql to the database to map to multiple rows?




Thanks a lot!

http://www.hibernate.org/ForumMailingli ... AskForHelp

Can you at least include your mapping files so that we can get a better idea of what you're doing ?

Already tried to select the B-objects as B-objects instead of selection the A-objects with type 'B'?



Best regards
Sven

May be I didn't describe my problem clear enough.

I have some condition needs to use the attribute in the parent table therefore, I need to use




because in the where clause I will use the attribute of A.

For example,




thanks for your suggestion!

best regards

Maybe if you'd follow the guidelines and include the necessary information, YOUR MAPPING FILE(s), we would better understand what you're asking.