VARIABLE TYPES IN PL/SQL PROGRAMMING:

a) While passing the values to arguments at Runtime, the PL/SQL variables can be treated as the types.\
       1) Bind Variables
       2) PL/SQL Variables

    1) Bind Variables:
           i) In PL/SQL to reference Bind variables, it must be prefix with a colon(:).
           ii) In SQL*PLUS the Bind variables has to be displayed using the PRINT command.
                   Ex:
                       Sql>    VARIABLE G_SALARY NUMBER;
                      
                       Sql>    DECLARE
                                   V_Sal NUMBER(7,2);
                               BEGIN
                                   SELECT Sal INTO V_Sal FROM Emp where Empno=7369;
                                   :G_Salary :=V-Sal;
                               END;
                      SQL>   PRINT G_Salary;
                      SQL>   SET ECHO OFF;
                      SQL>   SET VERIFY OFF;
                      SQL>   SET SERVEROUTPUT ON;
                      SQL>   ACCEPT B_NUMBER1 PROMPT 'Please Enter the first number:';                    
                      SQL>   ACCEPT B_NUMBER2 PROMPT 'Please Enter the secong number:';

                      SQL> DECLARE
                               V_Number1 NUMBER(9,2):=&B_Number1;
                               V_Number2 Number(9,2):=&B_Number2;
                           BEGIN
                               :Bind_Variable:=(V_Number1/V_Number2)+V_Number2;
                           END;
                      SQL> PRINT Bind_Variable;

        DISCUSS:  \Introduction\Vmethods\Bvari\Example1.sql
                           \Introduction\Vmethods\Bvari\Example2.sql

               SQL> SET ECHO OFF
               SQL> SET VERIFY OFF
               SQL> VARIABLE B_Total NUMBER
               SQL> ACCEPT B_Salary PROMOT 'Please Enter the Salary amount:'
               SQL> ACCEPT B_Bonus PROMOT 'Please Enter the Bonus Percentage:'
               SQL> DECLARE
                         V_Salary NUMBER(9,2):=&B_Salary;
                         V_Bonus NUMBER(9,2):=&B_Bonus;
                    BEGIN
                        :B_Total :=NVL(V_Salary,0)*(1+NVL(V_Bonus,0)/100
                    END;

               SQL> PRINT B_Total;

    2) PL/SQL Variables:
           i) These are substitution variables that are directly declared within the program.
           ii) These variables can be associated to the variables declared in ACCEPT command.
           iii) The PL/SQL variables can be projected using the DBMS_OTUPUT.PUT_LINE method within PL/SQL program.

             
                      SQL>   SET ECHO OFF;
                      SQL>   SET VERIFY OFF;
                      SQL>   SET SERVEROUTPUT ON;
                      SQL>   ACCEPT P_NUMBER1 PROMPT 'Please Enter the first number:';                    
                      SQL>   ACCEPT P_NUMBER2 PROMPT 'Please Enter the secong number:';

                      SQL> DECLARE
                               V_Number1 NUMBER(9,2):=&P_Number1;
                               V_Number2 Number(9,2):=&P_Number2;
                               V_RESULT(9,2);
                           BEGIN
                               V_RESULT:=(V_Number1/V_Number2)+V_Number2;
                               DBMS_OUTPUT.PUT_LINE(V_Result);
                           END;            
             
        DISCUSS:  \Introduction\Vmethods\Pvari\Example1.sql
                            \Introduction\Vmethods\Pvari\Example2.sql

               SQL> SET ECHO OFF
               SQL> SET VERIFY OFF
               SQL> SET SERVEROUTPUT ON;
               SQL> ACCEPT P_Salary PROMOT 'Please Enter the Salary amount:'
               SQL> ACCEPT P_Bonus PROMOT 'Please Enter the Bonus Percentage:'
               SQL> DECLARE
                         V_Salary NUMBER(9,2):=&P_Salary;
                         V_Bonus NUMBER(9,2):=&P_Bonus;
                         V_RESULT NUMBER(9,2);
                    BEGIN
                        DBMS_OUTPUT.PUT_LINE('The salary is the Bonus is Rs'||TO_CHAR(NVL(V_Salary,0)*(1+NVL(V_Bonus,0)/100)));
                    END;