Prentice Hall Oracle Plsql By Example 3Rd Edition [Electronic resources] نسخه متنی

Lab 5.3 Exercises

5.3.1 Use Nested IF Statements

In this exercise, you will use nested IF statements. This script will convert the value of a temperature from one system to another. If the temperature is supplied in Fahrenheit, it will be converted to Celsius, and vice versa.

Create the following PL/SQL script:

-- ch05_4a.sql, version 1.0
SET SERVEROUTPUT ON
DECLARE
v_temp_in NUMBER := &sv_temp_in;
v_scale_in CHAR := '&sv_scale_in';
v_temp_out NUMBER;
v_scale_out CHAR;
BEGIN
IF v_scale_in != 'C' AND v_scale_in != 'F' THEN
DBMS_OUTPUT.PUT_LINE ('This is not a valid scale');
ELSE
IF v_scale_in = 'C' THEN
v_temp_out := ( (9 * v_temp_in) / 5 ) + 32;
v_scale_out := 'F';
ELSE
v_temp_out := ( (v_temp_in 32) * 5 ) / 9;
v_scale_out := 'C';
END IF;
DBMS_OUTPUT.PUT_LINE ('New scale is: '||
v_scale_out);
DBMS_OUTPUT.PUT_LINE ('New temperature is: '||
v_temp_out);
END IF;
END;

Execute the script, and then answer the following questions: