More specifically, this invention relates to a query transformation technique to achieve {HEAD ~ more efficient query processing} of systems with {TAIL ~ varying query capabilities} within a federated system 
with
More specifically , this invention relates to a query transformation technique to achieve { HEAD ~ more efficient query processing } of systems with { TAIL ~ varying query capabilities } within a federated system
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH