conditional display value prompt (if no data exists)

[cogSteve]

Hi All -- what's the best way to render a prompt based off whether data exists for it or not??

Basically I have one value prompt with 'Types' that  is the cascade src for another that has 'Classifications'. If no Classifications exist, I dont want the prompt to appear at all, and a msg displaying instead (ie. No Classifications). I get errors whenever I create a variable based off a if-then calc in Classification prompt query (a flag that checks if any Classifications exist) and then tie it to a conditional block on which I have my value prompt.

All examples, and everything I've seen dont use data items in the variables (think the Cog docuementation says you cant do it), they all reference 'static choices' (ie. yes/no from src prompt in cascade).

Feel like I'm missing something really obvious. Anyone have any thoughts??

cheers,
Steve

[blom0344]

Would it no be straightforward to only show Types that have Classifications in the first prompt?