Questions with using Visio 2003 for dB design

Hello,

I'm trying to use Visio 2003 Enterprise Architect version to do a basic dB table design.  Can someone please help me out with the following questions:

1) how can I set a column to "auto-increment", with a seed value, and the increment amount?

2) once I've drag and dropped an Entity from the stencil onto the design surface and selected it, what is the difference between:

    a) clicking on a column name, select Edit, select Check tab, and enter the check constraints, versus

    b) clicking on "Check" under Categories, select Add (actually I'm not quite sure what to add here)

Thanks