When is the Seed method called in a EF code first migrations scenario?

Question

I'm new in a project and there is this class for the seed data:

 internal sealed class Configuration : DbMigrationsConfiguration<DAL.Context>
    {
        public Configuration()
        {
            AutomaticMigrationsEnabled = true;
        }

And this code to start the seed:

protected override void Seed(Context context)
    {
        try
        {

My question is: when is the Seed method called? Only when a user does update-database and the user doesn't have the database (basicly a new user), or also when the user with an existing database calls an update-database?

Answer 1

When it comes to the migrations Seed() method, coming from DbMigrationsConfiguration class, it's called every time when the Update-Database command is executed. Also when user calls it having existing database.

There is yet another Seed() method - it is a database initializer. It's invoked when database is creating and doesn't handle existing data (while seed from DbMigrationsConfiguration handles them, checking if specified entities exist).

Good to look up to One Unicorn blog for more information.