Oracle PL/SQL Programming: A Developer's Workbook

Expert

Q:
14-23.	You can’t simply add a second argument with a default value in this case; the earlier calls to calc.totals in the Oracle Forms applications don’t compile, because they haven’t passed values for all the arguments. You must instead rely on overloading: PACKAGE calc IS PROCEDURE totals ( department_id_in IN department.department_id%TYPE); PROCEDURE totals ( department_id_in IN department.department_id%TYPE, section_id_in IN INTEGER); END calc; Inside an Oracle Forms application, a developer can now call calc.totals in one of two ways, as shown in these examples: calc.totals (:emp.deptno); calc.totals (my_dept_var, :sections.section_id); Existing calls to calc.totals do not need to be changed; new calls to the calc.totals procedure providing a section will unambiguously be routed to the “second” implementation of the totals procedure.
Q:
14-24.	To remove the redundancies, you can use a local procedure (defined in the declaration section) to centralize all common code elements: PROCEDURE calc_percentages (total_in IN NUMBER) IS FUNCTION formatted_pct (val_in IN NUMBER) RETURN VARCHAR2 IS BEGIN RETURN TO_CHAR ((val_in/total_in) * 100, '$999,999'); END; BEGIN food_sales_stg := formatted_pct (sales.food_sales); service_sales_stg := formatted_pct (sales.service_sales); toy_sales_stg := formatted_pct (sales.toy_sales); END;
Q:
14-25.	This is a poorly designed function for a number of reasons: The function returns two different pieces of information: the company name as the RETURN value ...