Reg: Call By Value & Call By Reference

Question

Dear Gurus,
Can anyone give me the exact difference between Call By Value and Call By Reference in calling procedures. And also give me which one is call by value&reference in In,Out,In Out.
Cheers,
Jai

Answer 1

Hi Alex,
Simple and elegant explanation, but I do have a question.
Passing a variable to an argument of a procedure or a function which has been defined as out will consider it as null inside the sub program block until the value actually get changed inside it, then what is the need of pass by value to an argument defined as OUT (apart from the point the value gets copied back after the program completion)
create or replace procedure test_proc(a out number,b in out number) as
begin
dbms_output.put_line('A Value :'||a);
dbms_output.put_line('B Value :'||b);
end;
declare
val_a number := 10;
val_b number := 10;
begin
test_proc(val_a,val_b);
dbms_output.put_line('val_A Value :'||val_a);
dbms_output.put_line('val_B Value :'||val_b);
end;
PRAZY@11gR1> /
A Value :
B Value :10
val_A Value :
val_B Value :10
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.01And here A prints null even though we passed 10.
@OP: Pardon me for taking-over your thread.
Regards,
Prazy
Edited by: Prazy on Mar 26, 2010 2:49 PM