底层提供程序在开放实体框架上失败

Question

I am unsing entity framework in my web application. Earlier everything was working fine. But then I deleted database from Sql Server. After that whenever I run the application, I get the following exception :

The underlying provider failed on open entity framework  

Isn't it true that if we delete the database from Sql Server and again run the application, database is again created?

Answer 1

Entity framework will recreate your database on application start assuming the following:

• You have permission to create databases in SQL
• A connection string is specified correctly (if it was working before this should be fine)
• You are using CodeFirst or ModelFirst strategies for databases (ie if you generated an EDMX off an existing database it wont recreate it for you)

Answer 2

Can you show some details about connection string. I basically want to check the authentication you are using. Demo for setting a typical authentication : http://msdn.microsoft.com/en-us/library/ff649314.aspx

Another possibility can be with connection pooling. Try explicitly closing the connection(if there are any open connections)

db.Database.Connection.Close();

Answer 3

I had a similar error and it was due to the connection problem. Usually you need to open your *.EDPS file under your entity (EDML) and check your connection string and make sure it has got a correct setting especially your Default Oracle home.