How to Properly Test Controllers in ASP.net MVC that has database calls

I am working on an ASP.net MVC 3.0 Application. I am using MSTest along with Moq for unit testing. I have written all the test methods for my controllers and ran those tests , which gave successful results.

Now, I have a doubt whether I have properly made unit testing. Because, almost most of my controller actions contains database calls.

I am not mocking them , I am mocking only Session and Request objects using Moq.

Is it really necessary to mock database calls, since unit testing means testing a single unit of code? I think unit testing controller with database calls violates above statement.

If it is so, can any one explain me how to mock database calls? I am not using any Entity Framework.

Updated2:

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  public void AjaxSave(Model m)
{
   m.update(); // Database call
}