The system applies the transformed inexact query output to {HEAD ~ a heterogeneous datastore} to provide {TAIL ~ an output query result} 
to provide
The system applies the transformed inexact query output to { HEAD ~ a heterogeneous datastore } to provide { TAIL ~ an output query result }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL