The only difference I've found when a child entity is saving outside
of an association (has no magazine in your example) NH explicitly
inserts NULL to a FK (could be eliminated by
dynamic-update/dynamic-insert)
INSERT
INTO
Child
(Name, ParentId, Id)
VALUES
(@p0, @p1, @p2);
@p0 = 'Bob's Child' [Type: String (4000)], @p1 = NULL [Type: Guid
(0)], @p2 = 3a55de1d-fa69-4014-9c22-a0a600c876e8 [Type: Guid (0)]
All other things do work as before.
2012/8/7 Fabio Maulo <[email protected]>:
> It may work but the concept is not the same.
> The not-nullable FK mean that NH have to track the unidirectional
> one-to-many (in the domain model) because it have to work as a
> mandatory bidirectional one-to-many<->many-to-one in the DB.
> With a nullable FK the relation is just an option and NH does not have
> to track the backref to the parent.
> a case:
> we have a video as standalone entity or a video associated to a
> magazine. in this case the magazine may have a video associted in a
> collection. the association de-association is performed with an UPDATE
> because you can INSERT the video before INSERT the magazine and then
> you can perform the association beteween the two entities.
>
> if we have a reletion as "the video can exists just when associated in
> a magazine" the unidirectional association represents a real
> parent-child (the child can't exists without the parent) and the
> association/de-association is performed via INSERT-REMOVE, as in a
> bidirectional relation, but with a unidirectional relation in the
> domain model.
>
> btw the matter is always the same: you can change the behavior passing
> all tests and then wait for bugs ;)
> just take care to do it inside an alpha release (in this case)
> --
> Fabio Maulo
>
>
> El 06/08/2012, a las 18:00, "Alexander I. Zaytsev"
> <[email protected]> escribió:
>
>> Thanks, but I understand what this is and how it works. I do not
>> understand why this is applied only to not-null FK, as it works with
>> nullable FK too.
>>
>> If we will remove this check we will get consistent behavior for null
>> FK and for not-null FK
>>
>> 2012/8/7 Fabio Maulo <[email protected]>:
>>> The unidirectional one-to-many is a base feature of NH since 1.2 or
>>> before...
>>>
>>> What you are watching is a special case, exactly to manage and optimize the
>>> case when the FK is not-nullable.
>>> Instead INSERT+UPDATE, as managed for no-mandatory unidirectional
>>> one-to-many (where the "item" side may have its own lifecycle), the case for
>>> mandatory unidirectional one-to-many (FK not-nullable) works with INSERT
>>> directly using a "fake" property for the backref to the parent.
>>>
>>> On Mon, Aug 6, 2012 at 11:10 AM, Alexander I. Zaytsev
>>> <[email protected]> wrote:
>>>>
>>>> Hi, all
>>>>
>>>> As you may know NH since 3.2 supports uni-directional one-to-many
>>>> associations.
>>>>
>>>> This was done by these commits
>>>>
>>>>
>>>> https://github.com/nhibernate/nhibernate-core/commit/cb60f2169e7504ff83e601c555e42171f28ef9ff
>>>>
>>>>
>>>> https://github.com/nhibernate/nhibernate-core/commit/d6cc06bbfee56fc3ae224fdfdc862df4fdff0442
>>>>
>>>> I wonder why this fix is applied only to keys with not-null="true"
>>>> attribute? I've checked and it seems that all works perfectly without
>>>> checking that key is not nullable.
>>>>
>>>> As I understand the fix was ported from Hibernate, because there I've
>>>> found exactly the same code.
>>>
>>>
>>>
>>>
>>> --
>>> Fabio Maulo
>>>
