oracle11g - PLS-00201 compiling a procedure in SQL Navigator but not running the same as a script -

i have sql script referencing runs fine when use sql*plus user a.

if copy , paste code script in order make stored procedure in schama cannot compile objects references in schema b.

/* logged on schema sql navigator */ procedure myproc   myvar  b.mytable.my_column%type; begin   dbms_output.put_line('hello'); end ;

i error:

pls-00201: identifier 'b.mytable' must declared

but script, runs sqlplus logged user a

declare   myvar  b.mytable.my_column%type; begin   dbms_output.put_line('hello'); end ; / exit

why? how run script same user a?

Macro