EF Core automatic migration

In our way toward migrating an ASP.NET full framework application to ASP.NET Core 2.0 we encountered a significant change in EF Core 2.0 in comparison with EF 6.x.

 

EF 6.x

In EF 6.x we were tightly relying on automatic migrations in deployment operations. We never created or added a migration to the code-base. Instead we had turned on automatic migration and allowed data loss. So when new versions of the project were deployed on the server, all necessary changes on the database were done behind the scenes automatically.

I know that enabling automatic migration on a production server is not a good idea. But it was a constraint forced by our deployment team.

Entity Framework Core
Entity Framework Core

EF Core

Automatic migration has been removed from EF Core. This feature is not present in EF Core 2.0. There is no plan to add this feature to EF. Microsoft thinks it benefits is less than its drawbacks.

There are 2 methods in EF Core 2.0 related to migration. Database.Migrate() and Database.EnsureCreated(). Neither of them are a complete migration.

Migrate() does not add or create a migration. It only checks if any not-applied migrations exists or not. If yes, then updates the database based on them.

EnsureCreated() creates the database based on the models in the project. But it does not do this in the migration way. Actually no migrations are needed by this method. Disadvantage of this method is that a database created by it, can not be updated in future by any migrations. Indeed this method is added to EF to help people create projects fast in MVP style.

Conclusion

At the end, we decided to not having automatic migrations as EF 6.x. Everyone that creates a model is responsible to create migrations too. And never call EF command in the production server to update the database. Instead call the Migrate() method on each startup to take the database to the latest available migration.

A sample code would be like this:

 

Sample code inspired from here.