A family of Microsoft relational database management systems designed for ease of use.
There are a number of debug tools for this purpose. I'll usually set a "Breakpoint" by mouseclicking in the grey vertical bar to the left of the code window, next to some executable statement (i.e. not a Dim statement or a comment). You can then perform whatever form action calls the code (e.g. a button click, updating a control, whatever the event might be); the code will run up to the mark and stop. You can then use function keys (F8 steps one line of code, F9 runs the rest of the code, etc.) or equivalently use the options on the Debug menu.