How to add Foreign Key Properties subsequently to a Code First Model? - entity-framework

Question

Given the Model:
Public Class Customer
Property Id() As Guid
Property FirstName() As String
Property MiddleName() As String
Property LastName() As String
Property Addresses() As ICollection(Of Address)
End Class
Public Class Address
Property Id() As Guid
Property Name() As String
Property Street() As String
Property City() As String
Property Zip() As String
Public Property Customer() As Customer
End Class
Entity Framework 6 Code First has created a column called Customer_Id in my table Addresses. Now, I'd like to add a Property Customer_Id to my class Address that represents the existing foreign key relation:
Public Class Address
Property Id() As Guid
Property Name() As String
Property Street() As String
Property City() As String
Property Zip() As String
Public Property Customer() As Customer
//Added
Public Property Customer_Id() As Guid
End Class
Unfortunately this results in an InvalidOperationException while creating the DbContext saying:
The model backing the 'DataContext' context has changed since the database was created.
I tried different property names (with and without underscore, different casing). But still no luck. So, what is the correct way to add those properties subsequently without the need for migrations? I assume it's possible, because the model does not really change, I am only changing from an implicit declaration of a property to an explicit...
Update:
The responses show me, that I did not explain the problem very well. After some more reading I found the correct names now: I have an application which is installed several times at customer locations (therefore dropping and recreating the database is no option). Currently, it depends on Entity Framework's Independent Associations, but I want to have the Foreign Key in my entity as well (this is no change to the model, the foreign key is already there, but does not exist as a property in my entity, since this is currently only relying on the IA instead). I did not manage to add it without EF thinking my Database is outdated.

Answer 1

for me two ways :
drop table __MigrationHistory : that is have the new model runs, but forget migration functionalities
create a new db by changing the connection string of the application. Replace old __MigrationHistory by __MigrationHistory of the newly created db
Never tested the second solution, but it should work.
Before using any solution:
backup you db.
Before using first solution: are you sure you will never need migration functionalities ?

Answer 2

This exception is because you change your model. You have to set migration strategy. Please look at:
http://msdn.microsoft.com/en-us/data/jj591621#enabling
(edited)
First of all you have to remove that exception. Even if you didn't add any new column to your database your model has changed because you added new property to Address class. If you check your DB you will find dbo.__MigrationHistory table with Model column. Last (earliest) value from that column is used for checking that your model and DB are compatible. I'm not sure but I think that EF stores there binary serialized model. So the solution is - recreate DB or add migration (probably empty migration).
(edited)
When you want to set FK you can do this very simple by Data Annotations
// c# example
public class Address
{
...
public string CustomerId { get; set; }
[ForeignKey("CustomerId")]
public Customer Customer { get; set; }
}
or in fluent api
// c# example
modelBuilder.Entity<Address>()
.HasRequired(arg => arg.Customer)
.WithMany()
.HasForeignKey(arg => arg.CustomerId);
or look at:
http://weblogs.asp.net/manavi/archive/2011/05/01/associations-in-ef-4-1-code-first-part-5-one-to-one-foreign-key-associations.aspx
http://msdn.microsoft.com/en-us/data/hh134698.aspx