The present system applies {HEAD ~ the transformed inexact query output} to {TAIL ~ the heterogeneous datastore} and applies the local query element to a query result returned from the heterogeneous datastore to provide a query result 
to
The present system applies { HEAD ~ the transformed inexact query output } to { TAIL ~ the heterogeneous datastore } and applies the local query element to a query result returned from the heterogeneous datastore to provide a query result
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH