The following programs demonstrate the use of the relation clause
with a FOR loop. These programs declare a context variable E for
EMPLOYEES. This allows the programs to reference records from the
EMPLOYEES relation by using the variable E in the host language
print statements.
1 – C Example
#include <stdio.h>
DATABASE PERS = FILENAME "PERSONNEL";
main()
{
READY PERS;
START_TRANSACTION READ_ONLY;
FOR E IN EMPLOYEES
printf ("%s %s %s\n", E.LAST_NAME,
E.EMPLOYEE_ID,
E.SEX);
END_FOR;
COMMIT;
FINISH;
}
2 – Pascal Example
program context_variable (input,output);
DATABASE PERS = FILENAME 'PERSONNEL';
begin
READY PERS;
START_TRANSACTION READ_ONLY;
FOR E IN EMPLOYEES
writeln (E.LAST_NAME, ' ', E.EMPLOYEE_ID, ' ', E.SEX);
END_FOR;
COMMIT;
FINISH;
end.