public static void EnsureSeedDataForContext(this CityInfoContext context) { if (context.Cities.Any()) { return; } var cities = new List <City>() { new City() { Name = "New York City", Description = "The one with the big park.", PointsOfInterest = new List <PointOfInterest>() { new PointOfInterest() { Name = "Central Park", Description = "The most visited urban park in the United States", }, new PointOfInterest() { Name = "Empire State Building", Description = "A 102-story skyscraper located in Midtown Manahattan", } } }, new City() { Name = "Antwerp", Description = "The one with the cathedral that was never really finished", PointsOfInterest = new List <PointOfInterest>() { new PointOfInterest() { Name = "Cathedral", Description = "It was never completed because the city ran out of money" } } }, new City() { Name = "Paris", Description = "The one with the big tower", PointsOfInterest = new List <PointOfInterest>() { new PointOfInterest() { Name = "The Eifel Tower", Description = "The most visited tower in the world" } } } }; context.Cities.AddRange(cities); context.SaveChangesAsync(); }