Answer Posted / guru

Forward Declaration means.. If you are defining a package
body having two procedures , If u want to use second
procedure in the definition of first procedure.. You have to
declare the second package with its arguments (if have)
before using in the definition of first procedure. It’s
labeled as forward declaration

OR

EX1:


DECLARE
PROCEDURE P1 IS
BEGIN
dbms_output.put_line('From procedure p1');
p2;
END P1;
PROCEDURE P2 IS
BEGIN
dbms_output.put_line('From procedure p2');
p3;
END P2;
PROCEDURE P3 IS
BEGIN
dbms_output.put_line('From procedure p3');
END P3;
BEGIN
p1;
END;

Output:
p2;
*
ERROR at line 5:
ORA-06550: line 5, column 1:
PLS-00313: 'P2' not declared in this scope
ORA-06550: line 5, column 1:
PL/SQL: Statement ignored
ORA-06550: line 10, column 1:
PLS-00313: 'P3' not declared in this scope
ORA-06550: line 10, column 1:
PL/SQL: Statement ignored

Ex2:
DECLARE
PROCEDURE P2; -- forward declaration
PROCEDURE P3;
PROCEDURE P1 IS
BEGIN
dbms_output.put_line('From procedure p1');
p2;
END P1;
PROCEDURE P2 IS
BEGIN
dbms_output.put_line('From procedure p2');
p3;
END P2;
PROCEDURE P3 IS
BEGIN
dbms_output.put_line('From procedure p3');
END P3;
BEGIN
p1;
END;

Output:
From procedure p1
From procedure p2
From procedure p3


Thanks

Guru

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