Hi Fabio,
Row 5 can be A, B, and C, depending on which one I'm requesting.
The class hierarchy at A implements Id.
class A{
int Id{get;set;}
AProperty{get;set;} //Mapped to ColumnA in Table 1
}
class B : A {
BProperty{get;set;} //Mapped to ColumnB in Table 1
}
class C : B {
CProperty{get;set;} //Mapped to ColumnC in Table 1
}
B and C only map extra properties which are column projections.
CreateCriteria(typeof(A)).Add(Expression.Eq("Id",
5)).UniqueResult<A>()
CreateCriteria(typeof(C)).Add(Expression.Eq("Id",
5)).UniqueResult<C>()
The Database Identity of A and C are the same.
The only difference is that C includes C.AProperty, C.BProperty, and
C.CProperty projection. Where as A only has A.AProeprty projection.
Thanks,
Brian
On Oct 22, 7:54 am, Fabio Maulo <[email protected]> wrote:
> A row in the DB is the representation of the state of one object: which one?
>
> --
> Fabio Maulo
>
> El 22/10/2010, a las 11:40, Brian Chavez <[email protected]> escribió:
>
>
>
> > Hi Alan,
>
> > Thanks so much for the reply. I'm trying to avoid NHibernate using the
> > database to determine the type of object.
>
> > A single row in Table 1 can be projected into any object in the class
> > hierarchy.
>
> > For example, Row 5 is A, B, or C; depending on which type I'm
> > requesting.
>
> > If I CreateCriteria(typeof(C)), then NHibernate has enough information
> > to know what type I'm requesting.
>
> > I don't want NHibernate to extract type information from the database
> > (ie: discriminator) because class A, B, and C can all represent any
> > row in Table 1.
>
> > The only difference between A, B, and C classes is the projections of
> > the columns in the table.
>
> > I hope that clarifies my situation.
>
> > Any feedback would be appreciated!
> > -Brian
>
> > On Oct 22, 7:13 am, "[email protected]"
> > <[email protected]> wrote:
> >> You can use formulas as discriminators as opposed to a column. You
> >> obviously have some sort of logic that determines the object type?
>
> >> On Oct 22, 9:02 am, Brian Chavez <[email protected]> wrote:
>
> >>> Hello.
>
> >>> Problem:
>
> >>> I have 1 very large table of columns.
>
> >>> I have a class hierarchy that represents different projections of the
> >>> columns of this table.
>
> >>> For example:
>
> >>> class A{
> >>> AProperty{get;set;} //Mapped to ColumnA in Table 1
>
> >>> }
>
> >>> class B : A {
> >>> BProperty{get;set;} //Mapped to ColumnB in Table 1
>
> >>> }
>
> >>> class C : B {
> >>> CProperty{get;set;}
>
> >>> }
>
> >>> When I ask NHibernate to pull C, I expect to see C.AProperty,
> >>> C.BProperty, and C.CProperty.
>
> >>> Essentially, this class hierarchy represents different scoped
> >>> projected views of the *same* table.
>
> >>> How do I do this in hbm.xml mapping files without adding discriminator
> >>> values?
>
> >>> I've tried to use multiple <union-subclass> attributes and map to the
> >>> same table, but NH throws an exception:
>
> >>> --> NHibernate.DuplicateMappingException : Duplicate table mapping
> >>> Table 1
>
> >>> Any ideas?
>
> >>> Thanks,
> >>> Brian
>
> > --
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