PL/SQL Best Practices [13][If Statements]-Boolean Elements

You can code real Boolean variables and literals (TRUE, FALSE and NULL values) in PL/SQL.
Boolean variables and functions allow you to greatly improve readability of programs. You can hide complex expressions behind a name, which describes the expression.

Compare the two IF statements below.

   IF total_sal BETWEEN 10000 AND 50000 AND
      emp_status (emp_rec.empno) = 'N' AND
      (MONTHS_BETWEEN 
         (emp_rec.hiredate, SYSDATE) > 10)
   THEN
      give_raise (emp_rec.empno);
   END IF;

The second IF statement:

   IF eligible_for_raise (emp_rec.empno)
   THEN
      give_raise (emp_rec.empno);
   END IF;