Using Entity Framework (code first) migrations in production

Question

I'm just looking into using EF migrations for our project, and in particular for performing schema changes in production between releases.

I have seen mentioned that there is an API to perform these migrations at run-time using the DbMigration class, but I can't find any specific examples.

Ideally, I would want one DbMigration file for every database change, and for those changes to be applied automatically on application start up from the current version up to the latest version.

Answer 1

There is a Database Initializer you can use to achieve the migration to latest version on startup (or better, the dbinitializer will kick in on first db access), the MigrateDatabaseToLatestVersion, you use it like that:

Database.SetInitializer<ObjectContext>(     new MigrateDatabaseToLatestVersion<ObjectContext, Configuration>()); 

Regarding having one file per migration, if you enable automatic migrations you will find them in the Migrations folder (by default) in the root of your project.

Relevant info, with examples, here: http://weblogs.asp.net/fredriknormen/archive/2012/02/15/using-entity-framework-4-3-database-migration-for-any-project.aspx

Answer 2

This works too:

var configuration = new MyDbContextConfiguration(); configuration.TargetDatabase = new DbConnectionInfo(     database.ConnectionString, database.ProviderName);  var migrator = new DbMigrator(configuration); migrator.Update(); 

You can also call:

migrator.GetPendingMigrations(); 

to get a list of the migrations it needs to apply.