How to seed data with many-to-may relations in Entity Framework Migrations

Question

I use entity framework migration (in Automatic migration mode). Everything is okay, but I have one question:

How should I seed data when I have many-to-many relation

Answer 1

Ok. I understand how I should be in that situation:

protected override void Seed(Context context)
{
    base.Seed(context);
    var buyingItems = new[]
    {
        new BuyingItem
        {
             Id = 1,
             Price = 10m
        },
        new BuyingItem
        {
             Id = 2,
             Price = 20m,
        }
    }

    context.AddOrUpdate(new Parcel() 
    { 
        Id = 1, 
        Description = "Test", 
        Items = new List
        {
            buyingItems[0],
            buyingItems[1]
        }
    },
    new Parcel() 
    { 
        Id = 2, 
        Description = "Test2", 
        Items = new List
        {
            buyingItems[0],
            buyingItems[1]
        }
    });

    context.SaveChanges();
}

There are no duplicates in database.

Thank you, Ladislav, you gave me a right vector to find a solution for my task.