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: ADVANCED-DOTNET@DISCUSS.DEVELOP.COM 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 > > > > =================================== > > This list is hosted by DevelopMentor(R) http://www.develop.com > > > > View archives and manage your subscription(s) at > > http://discuss.develop.com > > > > =================================== > This list is hosted by DevelopMentor(R) http://www.develop.com > > View archives and manage your subscription(s) at > http://discuss.develop.com > =================================== This list is hosted by DevelopMentorR http://www.develop.com View archives and manage your subscription(s) at http://discuss.develop.com =================================== This list is hosted by DevelopMentor® http://www.develop.com View archives and manage your subscription(s) at http://discuss.develop.com
