note 64823 added to language.constants

If a variable has been declared and set value (e.g. $county='China'),but without changing it anytime,isn't it a constant(or at least like a constant).So,I also creat a constant in the way of declaring a variable. And now,I want to know whether there is any performance difference between them?Is it a good idea to use constant in this way? Who can tell me?Thank you. ---- Server IP: 66.163.161.117 Probable Submitter: 218.56.50.42 ---- X-Spam-Status: No, hits=3.1 required=5.0 tests=DATE_MISSING,FROM_NO_LOWER autolearn=no version=2.64 ---- Manual Page -- http://www.php.net/manual/en/language.constants.php Edit -- http://master.php.net/note/edit/64823 Del: integrated -- http://master.php.net/note/delete/64823/integrated Del: useless -- http://master.php.net/note/delete/64823/useless Del: bad code -- http://master.php.net/note/delete/64823/bad+code Del: spam -- http://master.php.net/note/delete/64823/spam Del: non-english -- http://master.php.net/note/delete/64823/non-english Del: in docs -- http://master.php.net/note/delete/64823/in+docs Del: other reasons-- http://master.php.net/note/delete/64823 Reject -- http://master.php.net/note/reject/64823 Search -- http://master.php.net/manage/user-notes.php