Using EF and MVC together - asp.net-mvc

Question

I would like to use Entity Framework 5 from which I can use one MVC Model that can span two or more databases.
Is this possible?
In other words, have one EF model that can use two or more databases. Because with MVC, you can only use 1 model in a View. Some of the data with some of the Views can come from different databases. In order to use the model binder in MVC and map it to EF 5 columns, I would need to accomplish this.

Answer 1

ASP.NET MVC is NOT dependent on Entity Framework.
ASP.NET MVC is a framework for building web application that stick with the Model View Controller pattern. It is not bounded to Entity framework. It can work with any data access technologies like LINQ2SQL / Entity Framework / Pure ADO.NET etc.. that means you can develop MVC application with or without using Entity Framework.
I assume you want to get data from 2 different databases and load a model object. You can do that by writing a select query which gets data from 2 databases and put that in a Stored procedure and put that proc in your database which your DbContext is communicating with. Then execute the stored proc and load the Model object.
a sample procedure which gets data from 2 databases
CREATE PROCEDURE GetCustomer(#id int)
AS
BEGIN
SELECT C.ID,A.DateReceived
FROM FirstServerName.DbName.dbo.Customer C
INNER JOIN SecondServerName.DbName.dbo.Applications A
ON A.CustomerID=C.CustomerID
AND A.CustomerID=#id
END
To execute the stored proc with Entity framework, you can use Database.SqlQuery method
var idParam = new SqlParameter { ParameterName = "#Id", Value = 414};
var result = context.Database.SqlQuery<Customer>
("exec GetCustomer #Id", idParam).ToList();
This will execute your proc and load the data to an instance of Customer class, assuming the result set structure and your model class structure look similar.
You may need to adjust the permissions of the stored proc to read data from the relevant databases /tables.

Answer 2

What Shyju is saying is that MVC doesn't care or know anything about your Entity Framework data model or database. As such, the idea that an MVC model can span two databases is like saying an airplane can span two hammers.

Answer 3

As above the M in MVC is whatever you want it to be. Microsoft don't specify what Model actually is. It certainly doesn't have to be an EF Model (although some code samples from MS use that as an example)
I'd suggest that M should be a ViewModel and should be unrelated to your data layer. Then use a tool like Automapper to map from a domain model to a ViewModel. The ViewModel encapsulates the data you want to show and any specific web view specific information that you want to display. Then when you post back the ViewModel you can use that to update the domain models appropriate fields etc and persist that to both databases. This is a good article on the subject of ViewModels http://lostechies.com/jimmybogard/2009/06/30/how-we-do-mvc-view-models/