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