Choosing between Data Access Block 5.0 or Entity Framework 4.0

I'm going to develop a Web Application with two essential requirements:

1. Total independence of DBMS. The application should work with different DBMS like Oracle, SQL Server and MySQL. 开发者_开发知识库That is, Client 1 use this application with SQL Server, but he wants to migrate to an MySQL Database. The application should be able to work with this new DBMS without needing to make changes to the application code. The only change I want to do is to change the connection string.

2. Scalability. ie, we will have a clustered SQL Server installation.

I know that Data Access Block is able to handle different DBMS and I assume it won`t be an issue to meet the scalability requirement, but I don't know if this is the case with Entity Framework.

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Choose Entity Framework, for a couple of reasons.

First, EF is where Microsoft is putting all its data access emphasis for the foreseeable future. Entlib's data block is primarily there to support folks already using it.

Second, Entlib will give you a regular API, but it doesn't insulate you from the differences in SQL statements. Oracle in particular does stuff with cursors no other database does (or needs to); EF at least attempts to give you a uniform API.

As far as scalability, that's all about the design of your database and application, no data access tool will give you that.