Entity Framework Code First: Configuration.cs seed or custom initializer

问题

I am working with the the Code First style of the Entity Framework for my first time. I want to set up some default data. The first approach I came across involved creating a custom initializer. I was headed this route but noticed after setting up migrations that it came with the Configuration.cs that already overrides the seed method just like the custom initializer.

internal sealed class Configuration : DbMigrationsConfiguration<Toolkit.Model.ToolkitContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = false;
    }

    protected override void Seed(Toolkit.Model.ToolkitContext 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" }
        //    );
        //
    }
}

So it seems there are two ways to accomplish this task. Can someone shed some light on what would be the recommended way of doing this? Or does it matter at all and I should just flip a coin?

回答1:

The Configuration.cs Seed method will run every time your model changes to make sure that some specific data stays in your DB, or to even possibly to reset that data to a specified default setting.

The Custom Initializer's seed method, on the other hand, can be setup to run every single time the application loads, like in this code, which is currently in the Global.asax file of my MVC page:

Database.SetInitializer(new MyCustomInitializer<MyDbContext, Configuration>());
var db = new MyDbContext();
db.Database.Initialize(true);

The practical difference really comes into play after you deploy your application. The Custom Initializer will make sure that no user can destroy some data that's absolutely required in your program.

来源：https://stackoverflow.com/questions/13980335/entity-framework-code-first-configuration-cs-seed-or-custom-initializer

标签

entity-framework

ef-code-first