休眠条件中LEFT_JOIN中的OR子句

Question

How can provide OR clause in LEFT_JOIN in hibernate criteria.

Criteria mainCrit=hibernateSession.createCriteria("Main.class");    
Criteria aPropertyCrit=mainCrit.createCrieria("child",CriteriaSpecification.LEFT_JOIN);

It generates sql as

select this_.Id,this_childId....
from main as this_
left join child as child1_ on child1_ .id=this_.childId
where.....

And I need to generate the sql as

select this_.Id,this_childId....
from main as this_
left join child as child1_ on child1_.id=this_.childId or child_.ParentId=this_.childId
where.....

How do I provide OR clause in LEFT_JOIN in above criteria.

Answer 1

The extending of the JOIN ... ON part, could be done, even with Criteria API. But only to be more restrictive, ie adding the AND part.

Take a look on the overloads of the createCriteria method, mostly the last parameter withClause :

Criteria createCriteria(String associationPath,
                        String alias,
                        JoinType joinType,
                        Criterion withClause)
                        throws HibernateException

Create a new Criteria, "rooted" at the associated entity, assigning the given alias and using the specified join type.

Parameters:

• associationPath - A dot-seperated property path
• alias - The alias to assign to the joined association (for later reference).
• joinType - The type of join to use.
• withClause - The criteria to be added to the join condition (ON clause)

In fact, any other approach (eg adding the OR) , is breaking the mapping principal, introducing the ability to have the cross join at the end. see Hibernate criteria: Joining table without a mapped association