In Oracle => symbol used for

Question

DECLARE
price_to_update NUMBER(6,2) := 20;

updated_price NUMBER(6,2) := 0;

BEGIN


dbms_output.put_line('price before ' || price_to_update);

dbms_output.put_line('updated_price before ' || updated_price);

changePrice (old_price => price_to_update, new_price => updated_price);

dbms_output.put_line('price_to_update after update ' || price_to_update);

dbms_output.put_line('updated_price after update ' || updated_price);

END;

/

in this example user is using => symbol i am unable to figure out for what purpose user using it ... KIndly Help me out ... thanks

Answer 1

It's the named notation for subprogram parameters (vs. positional notation). This syntax allows to:

1. Swap parameters.
2. Omit optional parameters.

Example:

PROCEDURE FOO(A VARCHAR2:=NULL, B VARCHAR2:=NULL, C VARCHAR2:=NULL)

... can be called as:

FOO(C=>'FOO', A=>'BAR');

Answer 2

It is called "named parameter notation". If you have this procedure:

procedure changeprice (old_price number, new_price number);

then you can call it with positional notation:

changeprice (price_to_update, updated_price);

or you can call it with positional notation:

changeprice (old_price => price_to_update, new_price => updated_price);

See documentation for more details.