它非常很简单，你将不得不使用实体框架，它自动根据数据库服务器转换sql查询。你将不得不支付
1：复制DAL类并将它们粘贴到DAL中，只需进行一些矿工更改，例如

（i）编写以SqlConnection为主的OracleConnection和OleDbConnection。 br />
它是一个完整的教程，可以解决你的问题



http://www.***.com/watch?v=aoFDyt8oG0k



http://www.***.com/playlist?list=PL6n9fhu94yhX5dzHunAI2t4kE0kOuv4D7

http://csharp-video-tutorials.blogspot.com/十分之二千零一十二/什么-是-ADONET部分-1.HTML

Hi Friends,

I am stuck in a problem and I need a little help. I am creating an application wherein I need to connect to a Database (MSSQL or Access or MySQL). Kindly suggest me to create a front end from where a user (client) can setup this information like: which server?, username?, password? and connection engine? etc.
Also, if I am not wrong, there is a difference between the SQL queries for Access, MSSQL and MySql so I need to create multiple classes to manage those also. Kindly guide me a little.
Thank you very much.

Tushar Srivastava

Its very easy, you will have to use entity framework, which translates sql queries according to the database server automatically. You will have to
1: Copy DAL classes and paste them in DAL, just do some miner changes like
(i) write OracleConnection insteated of SqlConnection, and OleDbConnection.
its a Complete Tutorial which can solve your problem

http://www.***.com/watch?v=aoFDyt8oG0k

http://www.***.com/playlist?list=PL6n9fhu94yhX5dzHunAI2t4kE0kOuv4D7
http://csharp-video-tutorials.blogspot.com/2012/10/what-is-adonet-part-1.html