Re: Inheritance in LINQ-SQL Framework and/or ADO.NET Entity Framework

> Does the ADO.NET Entity Framework support inheritance across assemblies?
> In other words, can I declare some "base" objects in one assembly, then in
> another assembly, inherit and extend those objects?

        Not sure, but I really don't think it's wise to do so anyway. Having
two schemas which have fields in common in perhaps a subset of the entities
isn't a reason to share code among the two projects: if one schema needs a
change in a table which is apparently 'the same' you are in trouble.

                FB

>
> Thanks,
> Mike
>
> On Wed, Sep 17, 2008 at 3:21 PM, Shawn Wildermuth <
> [email protected]> wrote:
>
> > Entity Framework or NHibernate both support the notion you looking for
> > though separating your data access without inheritance (e.g. composition
> > versus inheritance) might be a better solution overall.
> >
> > -----Original Message-----
> > From: Discussion of advanced .NET topics.
> > [mailto:[email protected]] On Behalf Of Mike Andrews
> > Sent: Wednesday, September 17, 2008 10:13 AM
> > To: [email protected]
> > Subject: Re: [ADVANCED-DOTNET] Inheritance in LINQ-SQL Framework and/or
> > ADO.NET Entity Framework
> >
> > Hi Lain,
> >
> > Thanks for the quick response.  I finally found the answer (through
several
> > online posts).
> > The current design of the LINQ-SQL system does not allow cross-assembly
> > inheritance nor conventional inheritance, per se.
> > Hopefully MS will rectify this situation with the next release or perhaps
> > the ADO.NET entity framework will work on this account.
> >
> > What I did find out is that I can mimic the behavior I need by using
> > interfaces.  I'm not exceptionally fond of this, but I'm going to give it
a
> > try.
> >
> > Thanks,
> > Mike
> >
> >
> > On Wed, Sep 17, 2008 at 3:45 AM, Iain Smallwood <[email protected]
> > >wrote:
> >
> > > Hi Mike,
> > >
> > > I do not use the dbml designer, as it seems to get a bit too complicated
> > > once you get many tables etc involved or want to change the schenma - I
> > > prefer SQLMetal, though it should amount to the same thing.
> > >
> > > I am not sure what is causing your problem but I am able to a) extend
the
> > > class in another assembly b) add extra gubbins to the class through an
> > > additional partial class in the same assembly, using this approach.
> > >
> > > From the look of your error I would suspect a critical difference in
some
> > > of
> > > the attribute decorations for the extra columns or something of that
> > > nature.
> > > Sorry if I am not much help - just trying to get going on this side of
> > > things myself and answered as no-one else did.
> > >
> > > cheers,
> > > Iain
> > >
> > > On Tue, Sep 16, 2008 at 9:26 PM, Mike Andrews
> > > <[email protected]>wrote:
> > >
> > > > I have a problem for which I cannot seem to discern a reasonable
> > > solution.
> > > > I would like to use the LINQ-SQL classes and objects for doing my
> > > database
> > > > manipulations but both seem to be lacking in the area that I need and
I
> > > > would like to know if any of you have a reasonable solution/answer (or
> > > just
> > > > to tell me it can't be done would be fine).
> > > >
> > > > I currently have a base set of classes setup in a dbml file and the
> > > > corresponding code (built using the built-in designer) contained in
> > > library
> > > > assembly.
> > > > I now want to re-use that work that was done and extend those classes
> > in
> > > > another assembly.
> > > >
> > > > For example, lets say have I have table Employee in the main database
> > > > schema
> > > > from which I'm deriving this project.
> > > > I now have a new database with the exact same schema save that the
> > > Employee
> > > > table now has an added column that was not previously present in the
> > > other
> > > > schema.
> > > > I want to be able to "inherit" the "Employee" class from the primary
> > > > assembly and extend it with an added column.
> > > > I have been able to accomplish this feat, and the designer seems to
> > > "allow"
> > > > this sort of behavior, however, an exception occurs when I try to
> > execute
> > > > the code.
> > > >
> > > > The exception reads:
> > > >
> > > > Data member 'System.Guid SetID' of type 'Lib1.Set' is not part of the
> > > > mapping for type 'E2Set'. Is the member above the root of an
> > inheritance
> > > > hierarchy?
> > > >
> > > > I'm really at a loss here on what to do next or how to overcome this.
> > >  Any
> > > > help would be most appreciated.
> > > >
> > > > Thanks,
> > > > Mike
> > > >
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