OT: DITA id attribute values

[Rick Quatro]

Hi Framers,

I am working on programmatically setting unique id values on all of the 
elements that require them in a DITA-based FrameMaker book. Are there any 
restrictions or recommendations for id values in DITA? My thought is to have 
a unique 3-character prefix for each book (i.e, "abc"), then I can generate 
a unique number suffix. So, an id might look like

abc_562387

or

abc-562387

Any advice will be appreciated. Thank you very much.

Rick Quatro
Carmen Publishing
585-659-8267
www.frameexpert.com