The system allows a user to create {HEAD ~ a semantic object data model} of {TAIL ~ the database schema} 
The system allows a user to create { HEAD ~ a semantic object data model } of { TAIL ~ the database schema }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL