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I have started working on a new project and am switching from LinqToSQL to EF 4.1 as my ORM.

I already have a database set up to work with and so am going with the database first approach. By default the EF generates a context which extends ObjectContext. I wanted to know if a good approach would be to replace it with DbContext.

Most of the available examples deal with only Code First and DbContextbut DBContext can be used with Database First too. Are there any advantages I get by using the DBContext? From what I have read the DBContext is a simplified version of the ObjectContext and makes it easier to work with. Are there any other advantages or disadvantages?

nighthawk457
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You will not replace anything manually. You will need DbContext T4 Generator available at VS Gallery. Don't touch your autogenerated files - your changes will be lost every time you modify EDMX file.

I answered similar question last year. Now my answer is mostly - for new users DbContext API is probably better. DbContext API is simplified - both in terms of usage and features but you can still get ObjectContext from DbContext and use features available only in ObjectContext API. On the other hand DbContext API has some additional performance impact and additional layer of bugs. In simple project you will probably not find any disadvantage in DbContext API - you will not see performance impact, you will not use corner features available only in ObjectContext and you will not be affected by occasional bugs.

A lot of information and blog posts was collected since DbContext API was released so you don't have to be afraid that you will not find description of the API. Also ADO.NET team now uses DbContext API as their flag ship.

I'm not a big fan of DbContext API but my opinion is not related to its functionality but to its existence - there is no need to have two APIs and split development capacity of ADO.NET team to maintain and fix two APIs doing the same. It only means that there is less capacity for implementation of really new features.

Community
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Ladislav Mrnka
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  • your link helped. I also wanted to know since I already have all my POCO classes created can I simply use the DbContext generator to add the two T4 template files, delete the template file for the poco entities and use my POCO entities without having to do much work. – nighthawk457 Feb 13 '12 at 18:22
  • You can but you must strictly follow [rules](http://msdn.microsoft.com/en-us/library/dd456853.aspx) for creation POCO entities (naming conventions) – Ladislav Mrnka Feb 14 '12 at 06:44
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I'm using it now with Oracle on an add on to an existing application. The simplification that Ladislav refers to works well for me on this project as I am short on time and resources. I have not found any gotchas as long as you stick to simple CRUD operations and less than ~150 tables.

You can still use metadata annotations to provide basic validation and localization and there is enough documentation out there but you won't find much on official Microsoft sites.

kevinskio
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