I’ve been working Entity Framework trying to get better with it. I’m liking what I’m seeing thus far but now have a question. With this new ‘Code First’ approach (from the CTP 4 download) we can now use EF from a code first approach, but I’m trying to find out if one can use an existing EDMX file with this approach.
I have a project I’m working on which has an EDMX file and I notice the ModelBuilder has a RegisterEdmx method but am not finding a lot out there on whether this will allow to use an existing EDMX file with my code first approach.
Also, I know with this new CTP things like RecreateDatabaseIfModelChanges are avilable but these options drop the database and recreate it, wont this cause all your data to be lost if you ever change your models? Is there something I’m missing here?
I can’t speak to using previously generated EDMX files but there is support to use Code First with existing databases. As for the automatic Recreate, yes, this will kill all your data. This is meant only in rapid development where the persistence of data doesn’t matter (and, in fact, is likely unwanted as you discover issues with business logic and want a clean start with your updates.)
This is meant only as a quick way to develop. As of (when Scott Guthrie blogged about the CTP – jump to section 5) there are no data migration features available. Your options are to manually update the database to match your model, delete the database and let it be recreated or set the automatic recreate option. Only the first option is non-destructive to your data.