protected ICollection<ABClass> ManyToManyWithProperties { get;set;}
public ICollection<B> Bs {
get{
return ManyToManyWithProperties.Select(ab=> ab.A).ToList();
}
}
Some examples about many-to-many mapping patterns
http://fabiomaulo.blogspot.com/2010/03/conform-mapping-many-to-many.html
On Mon, Nov 29, 2010 at 9:05 AM, Bartosz Pierzchlewicz <
[email protected]> wrote:
> Sorry Fabio, but I probably still don't understand you.
>
> You say, that I can have ABclass with additional properties and I do
> not have to remove ICollection<A> from B?
> How? If it is possible it solves my problem, but I still don't know
> how to map model.
>
> I don't see other solution than replace ICollection<A> in B with
> ICollection<ABclass>.
>
> Bartosz
>
> On 29 Lis, 12:29, Fabio Maulo <[email protected]> wrote:
> > emh... I think that you are mixing the persistence with what you are
> > exposing in your entity.
> > Even if, having properties, the relation have to be an ABclass with
> > two many-to-one nobody said that, in your A and B, you have to remove
> > the collection of Bs and As...
> > About the "change of logic": the fact that now the relation ifself has
> > properties, is a "change of logic"
> > --
> > Fabio Maulo
> >
> > El 29/11/2010, a las 05:36, Bartosz Pierzchlewicz
> > <[email protected]> escribió:
> >
> >
> >
> > > Thanks for your answer.
> >
> > > First your advice is equivalent to replacing many-to-many relation
> > > with one-to-
> > > many, one-to-one, many-to-one which we would like to avoid.
> > > Because this not only changes mapping, but also require change of
> > > logic. (B class has collection of A, but after change it will have
> > > collection of 'ab' classes, which has different meaning).
> > > I also tried to write 'ab' class as artifact (example above), but I
> > > think there is no way to access them without rewriting mapping from
> > > many-to-many.
> >
> > > Second advise, sounds reasonable, but I have no idea how to write
> > > mappings to make it works.
> >
> > > Could you please to give me example?
> >
> > > Bartosz Pierzchlewicz
> >
> > > On 28 Lis, 17:45, Fabio Maulo <[email protected]> wrote:
> > >> If the relation has additional properties you need an "artifact" to
> > >> represent the relation with relation-properties; the best candidate
> > >> as "artifact" is a class.
> >
> > >> The other option is the usage of a Dictionary where the key is the
> actual
> > >> many-to-many and the value is a component (a class containing only the
> > >> properties of the relation without the relation itself).
> >
> > >> On Thu, Nov 25, 2010 at 4:24 AM, Bartosz Pierzchlewicz <
> >
> > >> [email protected]> wrote:
> > >>> Thanks,
> > >>> but I'm not sure what you mean.
> > >>> Could you give me a example?
> >
> > >>> On 25 Lis, 07:04, Erendrake <[email protected]> wrote:
> > >>>> One thing i tried before was to add another relationship. You end up
> > >>>> with the ManyToMany as well as two ManyToOne with the AB table in
> the
> > >>>> middle. its not perfect but it worked for me in my app. hope it
> helps
> >
> > >>>> On Nov 24, 1:06 am, Bartosz Pierzchlewicz <[email protected]>
> > >>>> wrote:
> >
> > >>>>> Hi,
> > >>>>> My problem is easy to explain, but difficult to solve.
> > >>>>> We using NN 2.1. (rev 4896)
> > >>>>> I have two classes and many-to-many relation between them (sorry
> for
> > >>>>> using AR notation)
> >
> > >>>>> [ActiveRecord]
> > >>>>> public class A
> > >>>>> {
> > >>>>> [Property]
> > >>>>> public string NameA { get; set; }
> > >>>>> }
> >
> > >>>>> [ActiveRecord]
> > >>>>> public class B
> > >>>>> {
> > >>>>> [Property]
> > >>>>> public string NameB { get; set; }
> >
> > >>>>> [HasAndBelongsToMany(typeof(A),Table = "ab",
> ColumnKey
> > >>> = "b",
> > >>>>> ColumnRef = "a")]
> > >>>>> public ICollection<A> ACollection { get; set; }
> > >>>>> }
> >
> > >>>>> Now, I have to add some fields do ab table like modificationUser
> and
> > >>>>> modificationDate.
> > >>>>> So I wrote mapping class like that (I know, that we can use
> composite
> > >>>>> key):
> >
> > >>>>> [ActiveRecord]
> > >>>>> public class ab
> > >>>>> {
> > >>>>> [PrimaryKey]
> > >>>>> public int Id { get; set; }
> >
> > >>>>> [BelongsTo]
> > >>>>> public A a { get; set; }
> >
> > >>>>> [BelongsTo]
> > >>>>> public B b { get; set; }
> >
> > >>>>> [Property]
> > >>>>> public string ModificationUser { get; set; }
> >
> > >>>>> [Property]
> > >>>>> public DateTime ModificationDate { get; set; }
> > >>>>> }
> >
> > >>>>> Now comes the question: is there any way to access ModificationUser
> > >>>>> and ModificationDate fields?
> >
> > >>>>> I tried using EventListener, but no success.
> > >>>>> Maybe NH interceptors, or writing own custom CollectionPersister?
> >
> > >>>>> It is not solution for us to replace many-to-many relation with
> one-to-
> > >>>>> many, one-to-one, many-to-one, because ACollection is already used
> in
> > >>>>> many hql queries, and changing from ICollection<A> ACollection to
> > >>>>> ICollection<ab> ABCollection require to rewrite them all.
> >
> > >>>>> Thanks for any help.
> >
> > >>> --
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> Groups
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> > >>> To unsubscribe from this group, send email to
> > >>> [email protected]<nhusers%[email protected]>
> <nhusers%[email protected]<nhusers%[email protected]>>
> > >>> .
> > >>> For more options, visit this group at
> > >>>http://groups.google.com/group/nhusers?hl=en.
> >
> > >> --
> > >> Fabio Maulo
> >
> > > --
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