Update

To Replace master dataset data values by child dataset data values using relations
data empsalary;
input eid des $ salary;
cards;
101 tester 2500
102 programer 3000
103 analyst 4000
104 hr 4220
105 analyst 4300
;

data empnew ;
input  eid salary;
cards;
101 5000
103 3200
104 6432
;
proc sort data=empsalary;
by eid;
run;

proc sort data=empnew;
by eid;
run;

data emp_salaries;
update empsalary empnew;
by eid;
run;
proc print data=emp_salaries;
run;

/*remarks problems*/
data em1;
 input eid salary;
 cards;
 101 6234
 105 .
 102 .
 ;
proc sort data=em1;
by eid;
run;

data emp_s;
update empsalary em1;
by eid;
run;

data emp_sa;
update empsalary em1;
updtatemode=nomissingcheck;
by eid;
run;