EntityFramework Core automatic migrations

Question

Is there any code to perform automatic migration in Entity Framework core code first in asp.net core project?

I do it simply in MVC4/5 by adding

Database.SetInitializer(new MigrateDatabaseToLatestVersion<AppDbContext, MyProject.Migrations.Configuration>());
public Configuration() {
          AutomaticMigrationsEnabled = true;
        }

This saves time when entities changed

Answer 1

You can call context.Database.Migrate()in your Startup.cs

eg:

using (var context = new MyContext(...))
{
    context.Database.Migrate();
}

Answer 2

EF core doesn't support automatic migrations.So you have to do it manually.

From the perspective of automatic migrations as a feature, we are not planning to implement it in EF Core as experience has showed code-base migrations to be a more manageable approach.

You can read full story here : Not to implement Automatic Migrations

Answer 3

This is the way they do it in IdentityServer4 http://identityserver.io

public void ConfigureServices(IServiceCollection services)
{
    var connectionString = Configuration.GetConnectionString("DefaultConnection");
    var migrationsAssembly = typeof(Startup).GetTypeInfo().Assembly.GetName().Name;

    // Add framework services.
    services.AddDbContext<ApplicationDbContext>(options =>
            options.UseSqlServer(connectionString));
    ...
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    // this will do the initial DB population
    InitializeDatabase(app);
}

private void InitializeDatabase(IApplicationBuilder app)
{
    using (var scope = app.ApplicationServices.GetService<IServiceScopeFactory>().CreateScope())
    {
        scope.ServiceProvider.GetRequiredService<ApplicationDbContext>().Database.Migrate();
        scope.ServiceProvider.GetRequiredService<PersistedGrantDbContext>().Database.Migrate();
        ...
    }
}

Answer 4

Automatic migrations is not supported in EF Core. Migration it is necessary to create hands. To automatically apply all existing handmade migrations need to add the following code in the class Program:

public class Program
{
    public static void Main(string[] args)
    {
        var host = CreateWebHostBuilder(args).Build();

        using (var scope = host.Services.CreateScope())
        {
            var services = scope.ServiceProvider;

            try
            {
                var context = services.GetRequiredService<MyDbContext>();
                context.Database.Migrate(); // apply all migrations
                SeedData.Initialize(services); // Insert default data
            }
            catch (Exception ex)
            {
                var logger = services.GetRequiredService<ILogger<Program>>();
                logger.LogError(ex, "An error occurred seeding the DB.");
            }
        }

        host.Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseStartup<Startup>();
}

Answer 5

Following Microsoft's documentation

https://learn.microsoft.com/en-us/aspnet/core/data/ef-mvc/intro

If you are using dependency injection, first, you need to setup a static class Data/DbInitializer.cs and add the following code:

public static class DbInitializer
{
    public static void Initialize(ApplicationDbContext context)
    {
        context.Database.Migrate();

        // Add Seed Data...
    }
}

Notice, this is also where you can add seed data.

Next, in your Program.cs file, add the following code

public static void Main(string[] args)
    {
        var host = BuildWebHost(args);

        using (var scope = host.Services.CreateScope())
        {
            var services = scope.ServiceProvider;
            try
            {
                var environment = services.GetRequiredService<IHostingEnvironment>();

                if (!environment.IsDevelopment())
                {
                    var context = services.GetRequiredService<ApplicationDbContext>();
                    DbInitializer.Initialize(context);
                }
            }
            catch (Exception ex)
            {
                var logger = services.GetRequiredService<ILogger<Program>>();
                logger.LogError(ex, "An error occurred while seeding the database.");
            }
        }

        host.Run();
    }

In my case, I'm checking the environment to make sure I'm in development so I can control the migrations/updates. However, in production, I want them to be automatic for continuous integration. As others have mentioned, this is probably not best practices but on small projects it works great.