I was developing an application using Entity Framework and storing data in a .mdf database. My code can read the data, apparently it can save too, but only apparently. It get no erros, while the program is running it act like the data was saved, I can for example save an object, dispose the context, create a new one, and then when I search my object it's there! But when I query the database to see the stored data there's nothing there. If I close the app and run it again, all data is gone. Here's a example code I wrote just to test:

```
        using (DatabaseEntities e = new DatabaseEntities())
        {
            for (int i = 0; i < 50; i++)
            {
                User u = new User();
                u.Nome = "User" + i.ToString();
                e.AddToUser(u);
            }
            int c = e.SaveChanges(true);

            List<User> us = e.User.Where<User>(x => x.ID < 50).ToList<User>();

            foreach (User u in us)
                Console.WriteLine("ID: " + u.ID + " Hello from " + u.Nome);

            Console.ReadKey();
        }

```

When I run this I get the 50 outputs, if I look the content of the c variable in the debug, there's 50 changes, everythings seems to be fine, but when I start my query browser and look in the content of my MDF database, there's nothing there.

Probably it's something very simple but I can't see what it is, I need your help.