Getting multiple DbContexts to use Migrations with the same database

Question

Based on a sample MVC5 project I'm trying to learn the proper way to handle migrations.

In the root directory I have a folder called "DbContexts" with two Contextes.

First one: IdentityContext.cs

    public class IdentityContext : IdentityDbContext<ApplicationUser>
{
    public IdentityContext()
        : base("DefaultConnection")
    { }
}

then I have a folder called IdentityMigrations with the Configuration.cs

    internal sealed class Configuration : DbMigrationsConfiguration<TryFive.Web.DbContexts.IdentityContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = true;
        MigrationsDirectory = @"DbContexts\IdentityMigrations";
    }

    protected override void Seed(TryFive.Web.DbContexts.IdentityContext context)
    {
        //  This method will be called after migrating to the latest version.

        //  You can use the DbSet<T>.AddOrUpdate() helper extension method 
        //  to avoid creating duplicate seed data. E.g.
        //
        //    context.People.AddOrUpdate(
        //      p => p.FullName,
        //      new Person { FullName = "Andrew Peters" },
        //      new Person { FullName = "Brice Lambson" },
        //      new Person { FullName = "Rowan Miller" }
        //    );
        //
    }
}

Then I have MyContexts with similar properties.

When I try to run the "Update-Database" command I get this error message: The type 'TryFive.Web.DbContexts.IdentityContext' does not inherit from 'System.Data.Entity.Migrations.DbMigrationsConfiguration'. Migrations configuration types must extend from 'System.Data.Entity.Migrations.DbMigrationsConfiguration'.

Any idea on how to fix this or a better way to do this DbContext stuff?

Answer 1

Suggestion: If you are just doing a sample project to learn migrations as you say, stick to one DbContext. Keep it simple - merge your entities into one DbContext that inherits from IdentityDbContext<ApplicationUser>

Delete your existing migrations folders you've created - and re "enable-migrations" after deleting your second DbContext. This will help you to continue learning migrations, instead of learning how to use two DbContext's in one project.

Also, @Lajos, I'm not sure which MVC you are talking about, but my DbContext's have never inherited from DbMigrationsConfiguration - they inherit from DbContext, or IdentityDbContext. What you are referring to is the MigrationsConfiguration class that gets generated when issuing "enable-migrations" on a project. It is used for generating migrations and seeding data.