Multiple Document Interface (MDI): A MDI lets you open more than one record simultaneously. The MDI has a parent window, and any number of kid windows. The youngster windows typically share different pieces of the parent window's interface, including the menu bar, toolbar and status bar. Along these lines, a MDI is compelled to the parent window.  

Single Document Interface (SDI): A SDI opens each record in its own essential window. Every window has its own menu, toolbar, and section in the errand bar. In this way, a SDI isn't compelled to a parent window. This makes it simpler for the client to see the substance of the different windows.

MFC makes it simple to work with both single-record interface (SDI) and various archive interface (MDI) applications. SDI applications permit just each open report outline window in turn. MDI applications permit numerous report outline windows to be open in a similar example of an application.