{HEAD ~ The table display} acts as {TAIL ~ a window} into a database when it is selected by a user 
{ HEAD ~ The table display } acts as { TAIL ~ a window } into a database when it is selected by a user
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH