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