NHibernate HQL不支持“with”关键字吗？

Question

I'm trying to build a HQL that can left join values from a collection, in order to give me the chance of checking "is null" on it.

Taken from the example from hibernate manual:

from Cat as cat
    left join cat.kittens as kitten
        with kitten.bodyWeight > 10.0

doesn't seem to work in NHibernate, since it doesn't recognize the "with" keyword. How else are you supposed to left join and check for no-matching entries if you cannot specify join-clauses directly in your join as opposed to in your WHERE-statement?

I'm running NHibernate 2.0.0.

Answer 1

Unfortunately, this is not supported in NHibernate. It was first requested in 2005 and is by far the most popular requested feature.

Answer 2

I think you can workaround it by using an outer join, and then do this:

from Cat c
left join c.Kittens as kitten
where kitten.bodyweight > 10 or kitten.bodyweight is null

Answer 3

Apparently they're working on it ... https://nhibernate.jira.com/browse/NH-514

I've received an update report from the NHibernate JIRA yesterday, and this issue should be fixed in NHibernate v2.1.0 Alpha 3 :)