Temporal versions

INCUMBENTS:
   SSN,	     PCN,    START_DATE, END_DATE
111223333 , 900225 , 1996-01-01, 1996-06-01
111223333 , 120033 , 1996-06-01, 1996-08-01
111223333 , 120033 , 1996-08-01, 1996-10-01
111223333 , 137112 , 1996-10-01, 3000-01-01
444332222 , 120033 , 1997-01-01, 3000-01-01

POSITIONS:
   PCN    JOB_TITLE_CODE1  START_DATE  END_DATE
   900225 110689           1995-07-01  1998-03-01 
   137112 130891           1995-01-01  3000-01-01 
   999071 141955           1994-01-01  3000-01-01 
   120013 132955           1993-01-01  3000-01-01 

SAL_HISTORY:
   SSN         AMOUNT HISTORY_START_DATE HISTORY_END_DATE
111223333      52800  07/01/95           03/01/96
111223333      61300  03/01/96           07/01/96
111223333      72000  07/01/96           07/15/96
111223333      83000  07/15/96           12/31/99
444332222      40100  01/01/97           12/31/99
