Entity Framework Code-first default data in database

Question

How do I handle situations in which I need pre-existing data before the app is started or right after the database is generated. For example, I have a list of countries in which I'd like to load into the database after code-first generates it. How do I do this?

App is structured as follows:

Repository > Service > WebMVC

The xml is in the WebMVC project.

Answer 1

You create custom initializer, which inherits from DropCreateDatabaseIfModelChanges or DropCreateDatabaseAlways interface. Like:

public class EntitiesContextInitializer : DropCreateDatabaseIfModelChanges<-YourDbContext->

And then you overwrite Seed method like:

protected override void Seed(YourDbContext context)

Whole example might look like:

public class EntitiesContextInitializer : DropCreateDatabaseIfModelChanges<EntitiesContext>
{
    protected override void Seed(EntitiesContext context)
    {
        List<Role> roles = new List<Role>
        {
            new Role {Id=1, Title="Admin"},
            new Role {Id=2, Title="ProjectManager"},
            new Role {Id=3, Title="Developer"}
        };

        // add data into context and save to db
        foreach (Role r in roles)
        {
            context.Roles.Add(r);
        }
        context.SaveChanges();

    }
}

Edit: After setting this up, you have to set up Initializer too, as Ladislav Mrnka mentioned.

Database.SetInitializer(new EntitiesContextInitializer());

ie.: in Global.asax:

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();
    RegisterGlobalFilters(GlobalFilters.Filters);
    RegisterRoutes(RouteTable.Routes);
    Database.SetInitializer(new EntitiesContextInitializer());
}

Don't forget to add using System.Data.Entity; .....

Answer 2

You must create custom database initializer derived for example from DropCreateDatabaseIfModelChanges and fill data in overriden Seed method. Then you must use Database.SetInitializer to set your new initializer when application starts. Here is example (from CTP5) used to create custom index in the database.

Answer 3

For an example see the new MVC / Entity Framework tutorial series at http://www.asp.net/entity-framework/tutorials#Using%20MVC Both #1 and #4 show initializer classes.