Entity Framework FAQ

The EF FAQ has moved (and been updated substantially). 

It can now be found at http://www.ef-faq.org/


Comments (48)
  1. Frequently Asked Questions and Answers about ADO.Net Entity Framework The ADO.Net Entity Framework team

  2. One of the PMs on the team, Asad Khan, sent me a list of questions and answers which he culled from looking

  3. One of the best learning resources I have found since I joined my team at Microsoft is this page Danny

  4. One of the best learning resources I have found since I joined my team at Microsoft is this page Danny

  5. I’ve not spent near as much time on this as I would like, but this morning, I decided to do a quick update.

  6. I've not spent near as much time on this as I would like, but this morning, I decided to do a quick

  7. Whilst digesting some blogs today I came across; Kaxaml – this is looking like a better and better "XAMLPad"…

  8. markscottjohnson says:


    Have been toying with the EF for a while now and this is the most succint and useful article I have seen on some of the more contentious and advanced scenarios – thx.

    Am a big fan of nhibernate (and the POCO approach), can you recommned any good guidance/examples on implementing a codegen free approach you alude to in section 2.

  9. simmdan says:


    I’m glad you found it helpful.  For more information about building classes from scratch, I recommend looking at the following link to part of the MSDN docs:


    There’s some pretty good explanation there as well as a fair amount of sample code.  If you have additional questions, don’t hesitate to ask.

    – Danny

  10. rodrigo benin says:


    Have been exploring the EF and a friend at Microsoft Brasil pointed me this blog. Nice work! It’s a pretty good FAQ.

    I still got one question: the lastest EF version shipped with de VS 2008 SP1 Beta still doesn’t support entity inheritance? (such as Contact <- Person <- Customer for example) as posted in this FAQ at Question 7.2?



  11. simmdan says:

    Entity inheritance is supported and has been from the first CTP of the EF.  What question 7.2 is talking about is the idea of a property of an entity which is not itself an entity (it doesn’t have identity, it can’t participate in a relationship, etc.) but which does have some structure.  We call those complex types.  Complex types do not support inheritance and won’t for v1, but entities do support it.

  12. Just a quick note to point out a few interesting things about the updated version of the EF which shipped

  13. Daniel Simmons vient de publier sur son blog une FAQ de l’Entity Framework mise à jour avec la nouvelle

  14. Olá pessoal, tudo certo? Para quem anda acompanhando a evolução do Entity Framework, componente importante

  15. Danny Simmons , el cual trabaja en el equipo de Entity Framework y al cual tuve la oportunidad de conocer

  16. Daniel Simmons updated EF FAQ .

  17. Mohammad Tajari says:

    As I recall in traditional ADO.NET, it was possible to update a portion of a dataset in order to split persistance operations. Here if SaveChange method of ObjectContext has the ability of persisting some portions of modified and disconnected entities it would be great if I extend my created entities to Save themeself.

    As entities here are in disconnected mode so it might not all other entities receive the reflected changes by database and some exceptions might be thrown. But It is acceptable and I think it would be still great to be able to Save only a desired portion of entities.

  18. simmdan says:

    The EF does not have the ability to persist part of the changes to a context.  There are several reasons for this:

    1) The EF model includes entities and relationships as largely separate things while in the CLR object model they overlap quite a bit such that an entity has references to other entities which imply relationships.  If you were to save just an entity, for instance, there are some difficult questions about what that means to the relationships–especially once you look at concurrency checks, relationships which can be modeled either as foreign keys inline in a row or out in link tables, etc.

    2) The idea behind the context is a bit different from the dataset.  It’s not intended as a big in memory cache so much as something which represents a unit of work.  So if you have multiple changes to entities which you want to persist separately, the general recommendation would be to use separate contexts.

    – Danny

  19. Danny Simmons , del equipo de Entity Framework ha publicado una nueva actualización de su ya interesante

  20. Daniel Simmons updated EF FAQ . What are the changes? (from Daniel &#39;s post ). Updated: 1.2 Where

  21. 江南白衣 says:

    The Entity Framework enables developers to reason about and write queries in terms of the EDM model rather than the logical schema of tables, joins, foreign keys, and so on. Many enterprise systems have multiple applications/databases with varying degrees

  22. Jo-wen Mei says:

    veel handige info over Entity Framework

  23. Florian S. says:

    How to use Stored Procedures that only return simple data types like double, float and so on?

    Thanks in advance!

  24. Entity Classes &amp; Architecture Patterns Part of the Entity Framework FAQ . 2. Architecture and Patterns

  25. Entity Classes &amp; Architecture Patterns Part of the Entity Framework FAQ . 2. Architecture and Patterns

  26. Part of the Entity Framework FAQ . 6. Query 6.1. How is Span used? What is Span? (aka. How does the EF

  27. Part of the Entity Framework FAQ . 9. Object Services 9.1. What is ObjectContext.Detach() method used

  28. Part of the Entity Framework FAQ . 13. EDM 13.1. Does Entity Framework support Abstract types in EDM

  29. Part of the Entity Framework FAQ . 18. Multi-threading 18.1. What is the recommendation for running a

  30. As promised, the links from my session today on the new data stuff on 3.5 and 3.5 SP1. Thanks for listening.

  31. Presentation: Data and Data Access – State of the Nation Presenter: Eric Nelson http://blogs.msdn.com/ericnel

  32. Presentation: Presenter: Mike Ormond Presentation: Whats new in Data Presenter: Eric Nelson http://blogs.msdn.com/ericnel

  33. I’ve had a lot of questions lately on how to display data from two separate tables in the database into

  34. 罗爱军 says:


  35. Session 1 ADO.NEXT – Entity Framework &amp; Data Services Speaker: Eric Nelson http://blogs.msdn.com/ericnel

  36. I made a round of updates to the EF FAQ a while back but then had some trouble with the blog software

  37. Lately everyone in my team and around my bay have been talking about Entity Framework. Well since I have

  38. Lately everyone in my team and around my bay have been talking about Entity Framework. Well since I have

  39. Olá pessoal, tudo certo? Aqui no blog tenho aproveitado para falar bastante sobre os vários cenários

  40. Springy says:

    for being the first sticky thread at


    I miss ongoing information here.

    Where is the real EF source?

  41. santhosh yadav says:

    In my project i want to add an table in database that already exists using entity framework.if i want to add an column in table,how can do these pro grammatically not by UI.

  42. simmdan says:


    This kind of question is best posted to the EF forum (social.msdn.microsoft.com/…/threads) or to stackoverflow.

    Good luck,


  43. GoldyWang says:

    Is POCO dynamically derived from EntityObject?

    and can we custom the dynamic derived behavior?

    (Such as we let it implement some custom interface)

  44. simmdan says:


    No, the POCO objects aren't dynamically derived from EntityObject.  There are two ways for POCO to work:

    1) The POCO objects have no constraints on them–they don't derive from anything in particular and the EF doesn't create any new types that derive from them.

    2) The EF creates dynamic types which inherit from your POCO objects (not the other way around).

    Unfortunately there's not a mechanism built into the EF for customizing the dynamically created objects.  You might want to consider contacting Jeff Derstadt or Arthur Vickers who might be able to help you more.

    – Danny

  45. Pat says:

    Um, the new EF FAQ page is held by a domain squatter. Was it abandoned?

  46. dotnetqueries says:

    more interview questions can be find here


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