Model compatibility error

Question

Setup

I have an app that uses ASP.NET Identity 2.0. The identity part shares a database with the rest of the tables needed by the application. So in one class library, I have a dbcontext that accesses the database for business data, and in another class library, I have the IdentityModel.cs, ie, the ApplicationDBContext.

Problem:

All worked fine, until I got in a muddle, trying to figure out how to work with migrations with the business data context. I ended up deleting the __MigrationHistory table and hence all the model metadata in the database for both the context.

I now get the following error:

Model compatibility cannot be checked because the database does not contain model metadata. Model compatibility can only be checked for databases created using Code First or Code First Migrations.

I deleted all migrations related to the business data, and re enabled migrations for that project. That had the effect of recreating the model metadata for the business dbcontext.

However, I can't figure out how to achieve the same for the Identity metadata.

Question:

How do I recreate the model metadata in __MigrationHistory for ASP.NET Identity 2.0?

Answer 1

I had to recreate the database and start again. I am still in the dark to the extent that I don't know if Neel's answer is the correct one for a production database. Right now, I don't have the time to properly research AspNet.Identity to find the solution to the problem. Sorry.

Prevention before Cure:

What I DO know is that the problem would not happen if I hadn't deleted the __MigrationHistory table. So the issue is one of self harming and so prevention rather than curing is the best option.

Therefore, the moral of the story is:

Moral:

Never, EVER, delete the __MigrationHistory table. Learn a bit more about it BEFORE doing any thing quite so silly, feckless, carless and downright dumb.

Answer 2

Write below code in Global.asax.cs and try again...

Database.SetInitializer(new DropCreateDatabaseIfModelChanges<TsContext>());