I have to develop a desktop windows application in C#.Net 4.0 that will run in three different databases ie. MS Access 2007 onwards, Oracle 11G, and SQL Server 2008. Now I want to use Entity Framework in my application. Is this a best choice to use EF for my application ? If yes, then how can I use entity framework for Access database? Thanks in Advance.
You can use the EF with Microsoft Access using an Entity Framework provider for Microsoft Access. You can find an EF provider for Access
See this answer. Ask yourself why you need Access, could you use SQL Express instead? If you absolutely need Access then it would seem EF is not the right choice in this instance.
Putting Access to one side for the moment, it's perfectly possible to change data providers with EF (particularly code-first) as EF abstracts a lot of the database goo away from your code; depending on the database design it could be as simple as changing the connection string dynamically. The practical implications of this really do depend on your database design and the nature and complexity of the application you are building. See this question for example, here's another example.
We use Dapper as our ORM with repositories when working with MS Access. It's fantastic.
来源：https://stackoverflow.com/questions/11432488/how-to-use-entity-framework-for-ms-access-database