Users are given {HEAD ~ specific subsets} of {TAIL ~ the database information} to view at a given time, such as column definitions or the primary key definition 
Users are given { HEAD ~ specific subsets } of { TAIL ~ the database information } to view at a given time , such as column definitions or the primary key definition
OTH OTH OTH 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