EF 4.0 "Generate Database From Model"

Question

Hallo,

I have a Model with 2 inherited Entities (Product, ConcreteProduct). I generate a SQL DDL using "Generate Database From Model" (SQL Compact Server 3.5 SP1).

If I'll add a new "ADO.NET Entity Data Model" using the generated Database I get an Association and no Inheritance.

My Question is now, what is the "best" table design solution for inheritence in EF Framework?

Here the generated Code VS 2010:

....

ALTER TABLE [ConcreteProducts]
ADD CONSTRAINT [FK_ConcreteProduct_inherits_Product]
    FOREIGN KEY ([ID])
    REFERENCES [Products]
        ([ID])
    ON DELETE NO ACTION ON UPDATE NO ACTION;
GO

...

thx

Martin

Answer 1

Hi,

The "Generate Database From Model" uses a Table Per Type strategy (There are other inheritence strategies like Table Per Hierarchy and Table Per Concrete Type).
Since you tried to generate a model from the created database you get a naked model.
In order to use inheritence you will have to customize the model with Table Per Type strategy again (It isn't being done by EF for you).

I hope it will help you.

---

Gil Fink

Answer 2

Hello Martin,

 

Welcome to ADO.NET Entity Framework and LINQ to Entities forum!

 

How is the problem now?   I think Gil’s post is very helpful and informative for the question.   The default inheritance strategy for EF4 is the TPT inheritance.    For more about the how to use Model First and its “under the hood” information, please see

http://blogs.msdn.com/efdesign/archive/2008/09/10/model-first.aspx

http://blogs.msdn.com/adonet/archive/2009/05/12/sneak-preview-model-first-in-the-entity-framework-4-0.aspx

http://blogs.msdn.com/adonet/archive/2009/11/05/model-first-with-the-entity-framework-4.aspx

 

Have a nice weekend, both!

 

 

Best Regards,
Lingzhi Sun

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Answer 3

Hello Linzhi

Thanks Visual Studio 2010 works great. But I had probelms with the "impendance".

If you will work on both sides (SQL Server and entity model) at the same time you will get problems.

As an OO developer I prefer working with the entity model.

 

Best regards

 

Martin Lang

 

 

 

Answer 4

Hi Martin,

 

What’s the “impendance” issue you encounter now?   Model First lets us work on the entity model and it is really a fantastic feature I can imagine. 

 

Have a nice day!

 

Best Regards,
Lingzhi Sun

MSDN Subscriber Support in Forum

If you have any feedback on our support, please contact [e-mail]

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Answer 5

Hi Martin,

How is the problem now?    If you need any further assistance, please feel free to let me know.

Have a great day!

Best Regards,
Lingzhi Sun
MSDN Subscriber Support in Forum
If you have any feedback on our support, please contact [e-mail].  

---

Please remember to mark the replies as answers if they help and unmark them if they provide no help.
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