Comments on: Entity Framework Modeling: Table Per Type Inheritance

By: RobBagby

RobBagby — Thu, 11 Mar 2010 10:07:49 +0000

I believe that you would probably want to model that situation using containment vs. inheritance. There are some examples floating around doing what you want to do with a SP, but there are associated risks. This is one of the scenarios that Fowler used (I believe) to illustrate that we should favor containment over inheritance. Sorry I don’t have better news for you.

By: David Straley

David Straley — Wed, 10 Mar 2010 17:23:29 +0000

Wow! So THAT’S how to do inheritance! Why didn’t Microsoft make this more obvious?! This should be built-into the IDE Entity Framework window. If it weren’t for your post, I was about to give up on EF for my proof of concept for this new project — today!

Thank you,
David

By: Håkan H

Håkan H — Sat, 06 Mar 2010 23:01:58 +0000

Hi
Great article.
I have tested this (EF1) and have run into trouble when creating an object from any of the derived classes where there already exists an entity of the base class.
In you example, let’s say a person starts as a student (=a record is created in the PersonTPT and the StudentTPT in “one shot”, works fine with EF.
But after a while, the persons also becomes a Instructor. How to do this in EF?!

(Ripping my hair…)

By: TimW

TimW — Mon, 15 Feb 2010 22:43:48 +0000

Thanks for a great post – this helped me win the fight over the Entity Framework naysayers.

By: saurabh

saurabh — Sat, 02 Jan 2010 08:50:33 +0000

Hey, Thanks a lot….. You made it easy to understand.

Can you please tell me where can I find the sample code and the database.

By: Sam

Sam — Tue, 08 Dec 2009 21:06:28 +0000

What I find ridiculous about this technology is that no one has figured out how to MODIFY any of these derived types. Let’s say I have a Student that becomes and Admin or vis versa, or a Student that becomes a Business Student. There is no way to take an existing object and turn it into something else using these inherited objects… pretty silly if you ask me..

By: SoCal

SoCal — Sun, 06 Dec 2009 01:54:14 +0000

Thanks for the article. Following your steps, I was able to create a derived table and query it using Linq in about 2 minutes!

By: Manitra

Manitra — Mon, 19 Oct 2009 11:54:41 +0000

Hello,

Thanks for this great article, it’s an excellent start point for dealing with inhenritance in the entity framework.

Manitra.