Parent object is in EntityState.Unchanged, but it still inserted in the Database

I have a simple snowflake schema out of which I generated my Entity Framework model. The problem is that I am trying to map a child entity to an existing parent and/or grandparent entity, but it still inserts it. I followed this: Insert new object with existing object Prevent Entity Framework to Insert Values for Navigational Properties The interesting thing is that even though the EntityState of the parent entities is "Unchanged" the Entity Framework still tries to insert it. The Schema CarRepository.Save() method ``` public void Save(Car car) { using (DBContext context = new DBContext()) { // No need to save if it already exists if ( context.Cars.FirstOrDefault(x => x.RegistrationNumber == car.RegistrationNumber) != null) { return; } else { // Check if the parent POCOs exist in the DB. Model existingModel = context.Models.FirstOrDefault(x => x.Name == car.Model.Name); Manufacturer existingManufacturer = context.Manufacturers.FirstOrDefault(x=> x.Name == car.Model.Manufacturer.Name) Trader existingTrader = context.Traders.FirstOrDefault(x=> x.Name == car.Trader.Name) TraderCompany existingTraderCompany = context.TraderCompanys.FirstOrDefault(x=> x.Name == car.Trader.TraderCompany.Name) context.ContextOptions.LazyLoadingEnabled = false; //Attach to the context if existing in the DB, i.e mark the existing POCOs not to be added the DB if (existingModel != null) { car.Model = existingModel; Assert.IsTrue(context.ObjectStateManager.GetObjectStateEntry(car.Model).State == EntityState.Unchanged); } if (existingManufacturer != null) { car.Model.Manufacturer = existingManufacturer; Assert.IsTrue(context.ObjectStateManager.GetObjectStateEntry(car.Model.Manufacturer).State == EntityState.Unchanged); } if (existingTrader != null) { car.Trader = existingTrader; Assert.IsTrue(context.ObjectStateManager.GetObjectStateEntry(car.Trader).State == EntityState.Unchanged); } if (existingTraderCompany != null) { car.Trader.TraderCompany = existingTraderCompany; Assert.IsTrue(context.ObjectStateManager.GetObjectStateEntry(car.Trader.TraderCompany).State == EntityState.Unchanged); } //Mark the Car for Addition to the DB context.Cars.AddObject(car); context.ObjectStateManager.ChangeObjectState(car, EntityState.Added); //If the POCOs do not exist in the DB mark them for addition if (existingModel == null) { context.ObjectStateManager.ChangeObjectState(car.Model,EntityState.Added); } if (existingManufacturer == null) { context.ObjectStateManager.ChangeObjectState(car.Model.Manufacturer,EntityState.Added); } if (existingTrader == null) { context.ObjectStateManager.ChangeObjectState(car.Trader,EntityState.Added); } if (existingTraderCompany == null) { context.ObjectStateManager.ChangeObjectState(car.Trader.TraderCompany,EntityState.Added); } context.SaveChanges(); } } } ``` Edit: After a few days of tinkering I managed to come up with a workaround which worked for me. It seems that the Car that is being passed to the CarRepository.Save() has some kind of internal context which is undetectable... That being so, it is impossible to detach it from that context/s and add it to the one in CarRepository.Save(). In order to actually add it to this context I deep/lazy copy the Car object and its navigation properties, if existing. The workaround ``` public void Save(Car car) { using (DBContext context = new DBContext()) { // No need to save if it already exists if ( context.Cars .Any(x => x.RegistrationNumber == car.RegistrationNumber)) { return; } else { //Assign scalar properties to the deep copy Car carToBeSaved = new Car { carToBeSaved.RegistrationNumber = car.RegistrationNumber, carToBeSaved.Price = car.Price } //Car -> Trader -> ... if(car.Trader != null) { Trader existingTrader = context.Traders .FirstOrDefault(x => x.Name == car.Trader.Name); //If exists in DB assign, if not deep copy carToBeSaved.Trader = existingTrader ?? new Trader { Name = car.Trader.Name, JobTitle = car.Trader.JobTitle } //Car -> Trader -> TraderCompany if(car.Trader.TraderCompany != null) { TraderCompany existingTraderCompany = context.TradersCompanys .FirstOrDefault(x => x.Name == car.Trader .TraderCompany .Name); //If exists in DB assign, if not deep copy carToBeSaved.Trader.TraderCompany = existingTraderCompany ?? new TraderCompany { Name = car.Trader.TraderCompany.Name, Address = car.Trader.TraderCompany.Address, PhoneNumber = car.Trader.TraderCompany.PhoneNumber } } } //Car -> Model -> ... if(car.Model != null) { Model existingModel = context.Models .FirstOrDefault(x => x.Name == car.Model.Name); //If exists in DB assign, if not deep copy carToBeSaved.Model = existingModel ?? new Model { Name = car.Model.Name } //Car -> Model -> Manufacturer if(car.Model.Manufacturer != null) { Manufacturer existingManufacturer = context.Manufacturers .FirstOrDefault(x => x.Name == car.Model .Manufacturer .Name); //If exists in DB assign, if not deep copy carToBeSaved.Model.Manufacturer = existingManufacturer ?? new Manufacturer { Name = car.Model.Manufacturer.Name } } } //Mark the Car for Addition to the DB context.Cars.AddObject(car); context.SaveChanges(); } } } ``` If someone have any thoughts on this, please share. Thanks.