Change model after database is created on EF4 code only

Question

Hey, sorry for my bad english... Using EF4 code-only, I have created some POCO classes and my database was generated from that. All worked fine, I inserted some data on the tables but now I need to create a new property on one of my classes. If i just create it, the application give me the exception: {"The model backing the 'TestContext' context has changed since the database was created. Either manually delete/update the database, or call Database.SetInitializer with an IDatabaseInitializer instance. For example, the RecreateDatabaseIfModelChanges strategy will automatically delete and recreate the database, and optionally seed it with new data."}

I tried to create manually the field on the table, but it is still complaining... does someone know if there is a way and if so how can I manually update the database schema (i don't want to recreate it because i already have data) to match the model?

score 1 · Answer 1 · answered Nov 01 '10 at 21:52

1

EF generates partial classes. So you can add new properties(fields) in another partial class.

answered Nov 01 '10 at 21:52

Tom Vervoort

536
4
11

Tom, maybe I didn't express myself correctly... I have no problem on changing my classes, and I am using code-only (no edmx, see http://blogs.msdn.com/b/efdesign/archive/2009/06/10/code-only.aspx). What I want to know is how can I update manually the database to match my POCO classes, because after the database is generated, every change on the classes give me the above exception :/ – Leo Nov 02 '10 at 02:50

score 1 · Accepted Answer · answered Nov 02 '10 at 13:56

It should work if you make sure that your new column match exactly your new property.

For example, if you add a property NewProp

public class MyEntity
{
    [Key]
    public int Id;

    public string PropA;
    public int PropB;

    public int NewProp;

}

then in your database table MyEntities, you would add a column NewProp of type int not null.

What you can do to check if the column you add is correct, is to rename your database, then let Code-First recreate the database and see what's different between the original and new databases.

Thanks Christian, i have already tried to do that, but the problem was still happening because i was using CreateDatabaseOnlyIfNotExists and not null on Database.SetInitializer :/ - that was the missing link. But your answer give me the hint that I was looking at the wrong place :) — Leo, Nov 02 '10 at 19:36

Change model after database is created on EF4 code only

2 Answers2