Hi all,

we are using Hibernate 3.2.0 and Spring. No hbm.xml files, just annotations.
I wonder whether there is a way to configure Hibernate to fetch @OneToOne unidirectional relations in one select when fetching owning entity.
Entities are joined by FK.
For example

always produces a bunch of selects to retrieve 1-1 associations.

To get entity in a single select you have to explicitly specify left join fetch in JPQL query, none of config options or Hibernate annotations worked, for example

has no effect

Am I missing something here or is it the explicit query the only option ?

Thank you for any info

the explicit query is the expected option. It qllow fine grained choice.

According to JPA spec 1-1 associations are by default loaded eagerly. It is interesting why they then can't be loaded by default in a single query, or at least to have that configurable at association/class level. Now for big result sets this is certainly disadvantage in terms of performance and one has to explicitly specify fetch joins on associations to reduce roundtrips to datastore.
Any comments ?

I'm getting different behavior w/ Hibernate/Annotations 3.2.1/3.2.0 and 3.2.2/3.3.0.

FetchType.EAGER works with 3.2.1/3.2.0, but not with 3.2.2/3.3.0.

3.2.1/3.2.0 SQL:

Hibernate: select sidetasks0_.shipmentInfo_sideTasks_id as shipment4_3_, sidetasks0_.id as id3_, sidetasks0_.id as id1_2_, sidetasks0_.type as type1_2_, sidetasks0_.details as details1_2_, sidetasks0_.shipmentInfo_sideTasks_id as shipment4_1_2_, shipmentin1_.id as id0_0_, shipmentin1_.shipmentId as shipmentId0_0_, shipmentin1_.file as file0_0_, shipmentin1_.newShipmentForm_id as newShipm6_0_0_, shipmentin1_.currentTask_id as currentT5_0_0_, shipmentin1_.whitewaterJobId as whitewat4_0_0_, newshipmen2_.id as id3_1_, newshipmen2_.sendingUserImId as sendingU2_3_1_, newshipmen2_.sendingStationImId as sendingS3_3_1_, newshipmen2_.receivingUserImId as receivin4_3_1_, newshipmen2_.receivingStationImId as receivin5_3_1_, newshipmen2_.filename as filename3_1_ from ShipmentTask sidetasks0_ left outer join ShipmentInfo shipmentin1_ on sidetasks0_.id=shipmentin1_.currentTask_id left outer join NewShipmentFormEntity newshipmen2_ on shipmentin1_.newShipmentForm_id=newshipmen2_.id where sidetasks0_.shipmentInfo_sideTasks_id=?

3.2.2/3.3.0 SQL:

Hibernate: select shipmentin_.id, shipmentin_.currentTask_id as currentT6_0_, shipmentin_.newShipmentForm_id as newShipm
5_0_, shipmentin_.whitewaterJobId as whitewat4_0_ from ShipmentInfo shipmentin_ where shipmentin_.id=?

Hibernate: select newshipmen_.id, newshipmen_.filename as filename3_, newshipmen_.receivingStationImId as receivin3_3_,
newshipmen_.receivingUserImId as receivin4_3_, newshipmen_.sendingStationImId as sendingS5_3_, newshipmen_.sendingUserIm
Id as sendingU6_3_ from NewShipmentFormEntity newshipmen_ where newshipmen_.id=?

Query is simply: session.createCriteria(ShipmentInfo.class).list()

Did something change in 3.3.0?

you do not give enough information to say

plus the first one involve shipment task, the others not. It's suspicious :-)

using Annotations and Core, I can't reproduce, so wo a running test case...

Sorry, I got the selects confused with those of some other operation.