[support] Parsing QUERY_STRING

I have posted at http://drupal.org/node/361193 a request for information but have yet to hear anything back. So, I thought I'd try here. I am rewriting a web site from php4 to drupal 6. One important section of the old site uses QUERY_STRING to pass a parameter thusly: "../viewform/wcab10" The string "viewform" represents an actual page but "wcab10" is an index value. I'm trying to figure out how to do this with drupal. So far it looks as if I need to create nodes for all possible index field values. Rather I wish to land on viewform (node/xxx) and use "wcab10" as a parameter for a module (select * from table where index_field = "wcab10").