EF to ADO.NET transition

ado.net asp.net-mvc-3 dapper entity-framework

Question

Need suggestion for migration few modules of asp.net mvc 3 application: Right now we are using EF with POCO classes, but in the future for some performance driven modules we need to move to ADO.NET or some other ORM tool (may be DAPPER.NET).

The issue we are facing as of now is: our views dependent on Collection classes getting loaded through EF, what strategy should i used for these entity classes to be get loaded exactly the same way as by EF with some other ADO.NET or ORM tool.

What i want is to be able to switch between EF & ADO.NET with minimum of change at data access layer, as i don't want my Views to get effect by that.

Accepted Answer

You should use the Repository Design Pattern to hide the implementation of your data access layer. The Repository will return the same POCO's and have the same operations contracts no matter what data access layer you are using underneath the hood. Now this works fine if you are using real POCO's that do not have virtual methods for lazy loading in them. You will need to explicitly handle loading of dependent collections on entities to make this work.


Popular Answer

What I've seen so far, a seamless transition from one ORM/DAL to another is an illusion. The repository pattern as suggested by Kevin is a great help, a prerequisite even (+1). But nonetheless, each ORM has a footprint in the domain layer. With EF you probably use virtual properties, maybe data annotations or, easily forgotten, a validation framework that easily fits in (and dismiss others that don't). You may rely on EF's ability to map across join tables. There may be things you don't (but would like to) do because of EF.

(Not to mention tools that execute scaffolding on top of an EF context. That would make the lock-in even tighter.)

Some things I might do in your situation (forgive me if I'm stating the obvious for you)

  • Use EF optimally. (Best mappings, best associations, ...) Preparing for the future is good, but it easily degenerates into the YAGNI pattern.
  • Become proficient in linq + EF: there are many ways to needlessly kill performance with EF. Suppose EF is good enough!
  • Keep looking for alternatives for high performance, like using stored procedures, parallellization, background processing, and/or reducing data volumes, and choose one when the requirements (functional and non-functional) are clear enough.
  • Maybe introduce an abstraction layer with DTO's that serve your views now, and in the future can be readily materialized by another ORM or ADO.
  • Expose POCO's as interfaces, which can be implemented by other objects later.



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