I've got a little one-to-one problem.
I've got two classes with one-to-one relationship. For example: User and ContactInfo. Classes are bound together with primary keys. Relationship is uni-directional to be only possible to call user.getContactInfo(). Mapping for User looks as follows:



I've set outer join fetching ON and, so the load of a single user results in one SQL query joining User and ContactInfo tables. That's correct. But if I'd like all users with status=0, this HQL query results in n+1 SQL queries.



First it selects all Users with status=0 and than selects for each User all data from User joining ContactInfo. If I change the HQL query a little, result is only one SQL query, but the resultset is a Collection of arrays (User and its ContactInfo).


I know I can separate it in Java code, but I think there is much more elegant solution.

Thank for help. Sorry if this is a common problem, I wasn't able to find it here.


Pavel

Use left join fetch in your HQL

Is this 'left join fetch' supposed to work with 'key-many-to-one' relationships ? It seems not.
I also have this problem about n+1 SQL queries.

I tried to activate the proxies, but nothing changed.
A solution would be to use a different PK, and change the 'key-many-to-one' to a more simple 'many-to-one' relationship. (I wouldn't like this solution, since the db model would not be as smart and clean as it should be.)

Sadly, there's not much documentation about this key-many-to-one...

Thank you very much. That is exactly what I needed. Now my HQL looks like this:



avel