Sneak Preview: N-Tier development with Entity Framework 4.0

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Thu, 14 May 2009 22:11:18 GMT

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Sneak Preview: N-Tier development with Entity Framework 4.0 - ADO.NET Team Blog

DotNetShoutout — Fri, 15 May 2009 00:49:27 GMT

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re: Sneak Preview: N-Tier development with Entity Framework 4.0

Peter Goodman — Fri, 15 May 2009 04:54:29 GMT

Not sure if this is the right place to ask.

Will we have access to the changeset. It would be nice to be able to send just the changes over the wire. Also it would be nice to be able to construct a changeset from a dto changeset.

ADO.NET team blog : Sneak Preview: N-Tier development with Entity Framework 4.0

progg.ru — Fri, 15 May 2009 10:06:30 GMT

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re: Sneak Preview: N-Tier development with Entity Framework 4.0

Courtois — Fri, 15 May 2009 12:27:14 GMT

is this works with POCO object ?

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Jose — Fri, 15 May 2009 13:48:18 GMT

"is this works with POCO object ?"

=> I have the same question

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Craig Stuntz — Fri, 15 May 2009 14:50:34 GMT

These self-tracking entities thing looks good for what it is. Regarding the broader topic of n-tier development with Entity Framework, one of the concerns I have about the n-tier story coming out of Microsoft these days is that there are so many different solutions. For example, RIA services, Astoria/data services, WCF, etc. As you develop your n-tier story, it would be helpful if you could clarify where it fits into these other projects.

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Jeff — Fri, 15 May 2009 23:10:47 GMT

@ Courtois, Jose

Yes, the self-tracking entities will be POCOs in that they do not have any layering or metadata dependencies on the Entity Framework (i.e. no required EF interface, no required EF metadata, no required EF baseclasses). This is nice because you can use them with Silverlight.

The self-tracking entities will have fields in them that store the changes. You can use the T4 template we'll provide to generate these POCO entities for you and it will include all of the code needed to fill in these fields...but you never see this code when you use your entity as it's all private in the entity.

Jeff

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Jeff — Fri, 15 May 2009 23:13:12 GMT

@Peter

Yes, the changeset will be public in that there is a general way to declare the state of each entity and the relationship changes. The extension method "ApplyChanges" is done in such a way that you can feed in changes that come from other sources, like Java or your own code that creates this changeset. With our T4 self tracking entity template, the changeset will be part of the DataContract of each entity, but there is no reason why it needs to be there if you have some other way of using this changeset.

Jeff

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Peter Goodman — Wed, 20 May 2009 06:59:02 GMT

Can you tell us where in Beta 1 these "low level APIs"are? I am assuming there is some support in the core .Net Framework assemblies (not System.Data.Entity) that can represent change tracking data.

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Jeff — Thu, 21 May 2009 09:42:43 GMT

@Peter

The low level APIs that are described are on the ObjectContext class (ApplyOriginalValues), and on the ObjectStateManager (ChangeObjectState, ChangeRelationshipState).

Currently there is nothing outside of System.Data.Entity in the .NET Framework assemblies that represents change tracking data. Most of this information can be stored in standard collections such as List<T>. There is no "State" enum in mscorlib or System.Core, if that is what you are asking. This area is likely going to see some evolution (from EF and others), and hopefully more pieces will make their way into the base framework.

Jeff

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Ido Flatow — Wed, 10 Jun 2009 20:49:15 GMT

Please note a problem that exists with EF v1 when applying changes to an entity that has a scalar property of binary type - EF always sets binary properties to modified state, even if the content of the binary arrays are the same between the original and updated entity.

In our project we solved this change tracking by saving an additional crc for the binary property and re-calculating & comparing crc for the updated property.

We choose this option instead of saving original value because binary data is large and passing a message that holds both original and updated binary data is too expensive.

Entity Framework 4.0 Beta新特性

VS2010学习 — Thu, 11 Jun 2009 08:32:49 GMT

  Entity Framework 4.0 Beta 1（又称EF V2）与 .NET 4.0 Beta 1 一起发布，包含了一系列的重要改进：自定义代码生成、延迟加载、N层支持、POCO支持

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Ranes — Wed, 17 Jun 2009 07:49:44 GMT

Nice post, I am coming around to liking entity, I have been using it on MvcCms and once past the learning curve am becoming a real fan. Keep up the great work!

http://www.ranessoftwareconsulting.com/articles/8/map-my-fragments--why-i-like-entity-finally

re: Sneak Preview: N-Tier development with Entity Framework 4.0

radyo dinle — Sun, 19 Jul 2009 17:41:39 GMT

is this works with POCO object ?

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Nico — Sat, 03 Oct 2009 20:27:35 GMT

Nice article. Not often seen such a good work.

re: Sneak Preview: N-Tier development with Entity Framework 4.0

Ariel — Wed, 25 Nov 2009 23:54:00 GMT

I used the T4 template for creating self-tracking entities and tested with an example similar to the one you post here but when I made changes in the Client and post them back the changes are not saved in the DB because the State of the entity is kept as unchanged.

I guess that I making something wrong here but WHAT?

thanks,

Ariel