Positional Notation:

The first procedure call uses positional notation. A PL/SQL compiler related the first acct, actual parameter with the first formal parameter, acctno. and the compiler relate the second actual parameter amt along with the second formal parameter amount.

Named Notation:

The second procedure call uses is named notation. The arrow (known as an association operator) related the formal parameter to the left of the arrow with the actual parameter to the right of the arrow.

The third procedure call also uses named notation and displays that you can list the parameter pairs in any order. Thus, you need not know the order in that the formal parameters are listed.