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