Add migration with different assembly

Question

I am working on a project with ASP.NET CORE 1.0.0 and I am using EntityFrameworkCore. I have separate assemblies and my project structure looks like this:

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Answer 1

This is for EF Core 3.x.

Based on this answer from Ehsan Mirsaeedi and this comment from Ales Potocnik Hahonina, I managed to make Add-Migration work too.

I use Identity Server 4 as a NuGet package and it has two DB contexts in the package. Here is the code for the class that implements the IDesignTimeDbContextFactory interface:

public class PersistedGrantDbContextFactory : IDesignTimeDbContextFactory
{
    public PersistedGrantDbContext CreateDbContext(string[] args)
    {
        var configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json")
            .Build();

        var dbContextBuilder = new DbContextOptionsBuilder();

        var connectionString = configuration.GetConnectionString("db");

        dbContextBuilder.UseSqlServer(connectionString, b => b.MigrationsAssembly("DataSeeder"));

        return new PersistedGrantDbContext(dbContextBuilder.Options, new OperationalStoreOptions() { ConfigureDbContext = b => b.UseSqlServer(connectionString) });
    }
}

Compared to the answer of Ehsan Mirsaeedi I modified these: I added the MigrationsAssembly:

dbContextBuilder.UseSqlServer(connectionString, b => b.MigrationsAssembly("DataSeeder"));

Where the "DataSeeder" is the name of my startup project for seeding and for migrations.

I added an options object with ConfigureDbContext property set to the connection string:

return new PersistedGrantDbContext(dbContextBuilder.Options, new OperationalStoreOptions() { ConfigureDbContext = b => b.UseSqlServer(connectionString) });

It is now usable like this: 'Add-Migration -Context PersistedGrantDbContext

At this point, when a migration has been created, one can create a service for this in a migration project having a method like this:

public async Task DoFullMigrationAsync()
        {
            using (var scope = _serviceProvider.GetRequiredService().CreateScope())
            {
                var persistedGrantDbContextFactory = new PersistedGrantDbContextFactory();

                PersistedGrantDbContext persistedGrantDbContext = persistedGrantDbContextFactory.CreateDbContext(null);
                await persistedGrantDbContext.Database.MigrateAsync();

                // Additional migrations
                ...
            }
        }

I hope I helped someone.

Cheers,

Tom