emp(bob, 8000, r_d, (940101, 940701)).
emp(bob, 6000, salesDept, (950101, 950601)).
emp(bob, 7000, salesDept, (950601, 951001)).
emp(bob, 7000, r_d, (951001, 960201)).
emp(bob, 7000, humanResource, (960201, 970101)).