遍历删除所有序列名（sequence）

declare
   cursor secur is
	select * from user_sequences;
   rec secur%rowtype;
begin
    open secur;
    loop
	fetch secur into rec;
	exit when secur%notfound;
	execute immediate 'drop sequence ' || rec.sequence_name;
    end loop;
    close secur;
    commit;
end;
/