PL/SQL difference between DEFAULT and assignment operator

Question

I'm newbie in PL/SQL and this question might seem to be 'childish' so I'm sorry in advance, but Google didn't help me at all...

Is there any difference between following procedures?

Procedure p1(a Number DEFAULT 0) Is
Begin
    DBMS_OUTPUT.put_line(a);
End;


Procedure p2(a Number := 0) Is
Begin
    DBMS_OUTPUT.put_line(a);
End;

I have checked them, so when I call both of them without args the output is 0, but I'm not sure if there are any side effects.

Answer 1

If you follow Oracle's documentation

You can use the keyword DEFAULT instead of the assignment operator to initialize variables. You can also use DEFAULT to initialize subprogram parameters, cursor parameters, and fields in a user-defined record.

Use DEFAULT for variables that have a typical value. Use the assignment operator for variables (such as counters and accumulators) that have no typical value.

DECLARE
    blood_type CHAR DEFAULT 'O';         -- Same as blood_type CHAR := 'O';
    hours_worked    INTEGER DEFAULT 40;  -- Typical value
    employee_count  INTEGER := 0;        -- No typical value

  BEGIN
    NULL;
  END;
  /

So I guess internally is the same.