Entity Framework Self-Tracking Entities not recommended by Microsoft

Asked 17/9, 2012 at 15:19 Answered 18/11, 2013 at 13:30

Solved c#.net entity-framework self-tracking-entities

While looking at Microsoft's web site, I discovered that they no longer recommend using Self-Tracking Entities.

Each link below is a MS resource that mentions not to use STEs:

Shows what templates are available by the Entity Framework team: EF Designer Code Generation Templates
Self-Tracking Entities
Recommended technologies for N-Tier applications

Does anyone know why Microsoft no longer recommends using STEs?

Vial answered 17/9, 2012 at 15:19 Comment(4)

Didn't you ask almost the same question earlier today? – Korney 17/9, 2012 at 15:22

Not being Microsoft, I can only guess what the reason is. That said, requiring every tier above the model tier to include a correct implementation of the self-tracking logic sounds like the exact opposite of what using an N-Tier architecture is supposed to achieve to begin with. E.g. you can't really expose your service layer over interoperable web services easily. Another hypothesis is that STEs sound fairly "magic", and probably end up not doing what users want with no way to customise the behaviour. – Paranymph 17/9, 2012 at 15:26

It says right in one of your links "Self-Tracking Entities can not be used with Code First models" – Shovelboard 17/9, 2012 at 16:13

@Korney I did not ask the question in the post you linked. This is a coincidence. When I posted my question, that one didn't exist yet. – Vial 18/9, 2012 at 14:31

(NOTE: As I don't work for MS this is all conjecture based on their public statements and past history).

The first article you posted "sort of" explains the reason, though not very clearly: they want you to use a better alternative and have no intention of fixing or improving STEs. Microsoft is putting STEs into the bin of 'early failed experiments', similar to RDO or Remoting or LINQ2SQL -- they put something out to see how well it worked and it just didn't.

In general, it was always acknowledged by Microsoft that STEs were a first-stab at solving a real business problem but that they were clearly incomplete. In particular, they were really bad at attaching object graphs with shared entities, they didn't support lazy loading, and had a number of other miscellaneous limitations.

MS has apparently decided they're not going to try to clean them up (notice that they've also deprecated the POCO template, for similar reasons). Since they aren't planning to fix or improve the template, they want people to stop using it for new projects and move on to the better alternatives:

MSDN data library

DbContext Generator

This template will generate simple POCO entity classes and a context that derives from DbContext. This is the recommended template unless you have a reason to use one of the other templates listed below.

STEs existed mostly to support cases where entities were being disconnected and reconnected to their context, especially in serialization scenarios (WCF or web services, for example). In "standard" Entity Framework objects, all of the change tracking was done in the context, and attaching an existig entity to a context was problematic. STEs made that process easier, but at the cost of making almost everything else really hard.

From what I have seen and experienced about the DbContext it is supposed to be a better alternative to solve this problem, though it doesn't actually replicate what STEs did. The general consensus among heavy users of EF seems to be that serializing your EF entities end-to-end is a really bad idea. Instead you should be using DTOs and something like AutoMapper to map between your DTO and EF objects.

Debenture answered 17/9, 2012 at 16:32 Comment(1)

+1, not bad for a conjecture. For Visual Studio 2012, creating an edmx model will automatically include the [currently] recommended T4 templates which should make it easier for those getting started and give a decent "default option". – Hellenist 1/10, 2012 at 22:22

I authored Trackable Entities as a replacement for STE's: https://trackable.codeplex.com. It's deployed as a set of NuGet packages and Visual Studio extensions. There are a set of project templates, with T4 templates for ASP.NET Web API scaffolding, as well as item templates for generating WCF services.

Here is a blog post I wrote comparing TE's with STE's: http://blog.tonysneed.com/2013/11/18/trackable-entities-versus-self-tracking-entities.

Cheers, Tony Sneed

Lillie answered 18/11, 2013 at 13:30 Comment(0)

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