How to get entity framework to realize the model and the DB are in sync

Question

I am using Entity Framework code first for the first time in a production environment. Everything went fine until we got the DB up and had put some of the data in it and then to get some of the data we were importing from another location we had to change field lengths. So we made some of the fields nvarchar(99) instead of nvarchar(50).

That went fine and the application still worked but I knew I needed to change the data annotation or it would blow up later when it loaded and tried to save a too long field. When I did that the app blew up even though the model and the db are now matching. So I thought that it was the hash in the metadata table so I thought I'd be clever and make a new DB and take the hash from there and copy it. That did not work and in fact now I cannot get my app to connect to the test db that we have data loaded in at all.

I do not want to drop and recreate this database. I want entity framework to realize that the model and the schema do in fact match. Is there any way for me to do this? Also why did copying the metadata from a DB that entity framework created with this model not work?

Answer 1

Entity Framework Code First creates a EdmMetadata table and saves a hash of your Model classes in it. When you change something in the Model, the hash of the new Model classes doesn't match what's in the EdmMetadata table anymore, and the app should "blow up" at runtime. What you need to do to keep using the same database without dropping it, is to delete the EdmMetadata table. This way EF will not do that check and will try to proceed with the access to the DB.

Check this video tutorial (skip to 8:10 of the "When Classes Change" section).