stored procedure

1. Create and use stored procedures

          grammar : 

                 create or replalce PROCEDURE The process of ( parameter list )

                  as

                    PLSQL Subroutine body ;

eg: -- The first stored procedure : Print Hello World   No parameter list 
   
    /*
         Calling stored procedure :
            1. exec sayHelloWorld();    -- Call only once 
            2. begin
                    sayHelloWorld();
                    sayHelloWorld();
                    -- Call it several times 
               end; 
                 /
    */

    create or replace procedure sayHelloWorld
    as
    -- The explanatory part 
    begin
        dbms_output.put_line("Hello World");
    end;
      /

eg2: -- Stored procedure with parameters 
     --: For designated employees , rose 100 Dollar wages ; And print the salary before and after the rise 

 /*
     How to call :
    begin:
        raisesalary(123);
        raisesalary(321);
      commit;   -- Ensure that the above two calls are from the same thing 
    end;
    /

  */
create or replace procedure raisesalary(eno in number)
-- Stored procedure with parameters , It is necessary to indicate that this parameter is an input parameter (in) Or output parameters 
as
    -- Define a variable to save the salary before the rise 
    psal emp.sal%type;
begin
    -- Get the salary before the employee gets a raise 
    select sal into  psal from emp where empno = eno;

    -- Give the employee a raise 100
    update emp set sal = sal + 100 where empno = eno;

    -- Be careful : Generally, it is not in stored procedures or stored functions ,commit and rollback

    -- Print 
    dbms_output.put_line(' Before rising  : '||psal||'  After rising  : '||(psal + 100));
end;
/