K3/EES 4/482-15 15.5.98
Using a database oriented DTD
Query language requirements
uquerying multiple instances simultaneously
uaccessing any information in the instance in any order
ucascading queries
uapplying any condition at any point
ukeep results of subqueries for later use
ucombining results of queries such as union, intersection etc.
uresult of the query can be anything from single value to an entire tree
uoptimizing performance by introducing auxilliary data structures