Packaged variables and triggers

Question

I am creating a trigger taht will update the values of packaged variables.
I need some help getting the variables to work correctly...here's the code and issues:
-------------PACKAGE SPECIFICATION------
CREATE OR REPLACE PACKAGE discount_pkg
IS
pv_disc_num  NUMBER;
pv_disc_txt  VARCHAR2(50);
END;
------------DECLARE VARIABLES-----------
BEGIN
discount_pkg.pv_disc_num:=5;
discount_pkg.pv_disc_txt:='N';
end;
--------------TRIGGER 9:5----------------
CREATE OR REPLACE TRIGGER bb_discount_trg
AFTER UPDATE OF orderplaced ON bb_basket
FOR EACH ROW
BEGIN
IF :NEW.orderplaced=1 THEN
IF discount_pkg.pv_disc_num=5 THEN
  discount_pkg.pv_disc_txt:='y';
END IF;
END IF;
END;
/And the resulting test reveals the following errors:
SQL> update bb_basket
  2  set orderplaced=1
  3  where idbasket=13;
1 row updated.
SQL> print pv_disc_num;
SP2-0552: Bind variable "PV_DISC_NUM" not declared.
SQL> print discount_pkg.pv_disc_num;
SP2-0552: Bind variable "DISCOUNT_PKG" not declared.Any idea why this is happening?

Answer 1

SQL> print pv_disc_num;
Print statement can only be used to display the value of environment variable. In your case, you are trying to display the value of a variable in a package. To display a value of a variable in a package, you need to retrieve it using pl/sql block. Try this:
begin
dbms_output.put_line(discount_pkg.pv_disc_num);
end;
if you want to use the PRINT syntax, you need to declare an environment variable to store the value:
SQL>variable pv_disc_num NUMBER
SQL>begin
:pv_disc_num := discount_pkg.pv_disc_num;
end;
SQL> print pv_disc_num