wp-how-to-use-petapoco-with-umbraco-06.cs

var jc = new Director
{
    FirstName = "James",
    LastName = "Cameron"
};

dbContext.Database.Insert(jc);

var avatar = new Movie
{
    DirectorId = jc.Id,
    Title = "Avatar",
};

dbContext.Database.Insert(avatar);

var sw = new Actor
{
    FirstName = "Sam",
    LastName = "Worthington"
};

var zs = new Actor
{
    FirstName = "Zoe",
    LastName = "Saldana"
};

dbContext.Database.Insert(sw);
dbContext.Database.Insert(zs);

dbContext.Database.Insert(new ActorMovie
{
    ActorId = sw.Id,
    MovieId = avatar.Id
});

dbContext.Database.Insert(new ActorMovie
{
    ActorId = zs.Id,
    MovieId = avatar.Id
});