drop and create sequence from a stored procedure

因應跨年度，收據編號要歸0問題，須重建 sequence。


CREATE OR REPLACE PROCEDURE my_proc
IS
   l_seq_start_with number := 0;
begin
   begin
      execute immediate 'DROP SEQUENCE MY_SEQ1';
   exception
      when others then null;
   end;
   execute immediate
      'CREATE SEQUENCE MY_SEQ1 START WITH '
         ||to_char(l_seq_start_with)
         ||' INCREMENT BY 1 NOCACHE';
end;