Is there some methods like 'datareader' in MySQLdb for handling mass data

[Jeremy.Chen]

hi all:
  when I handled mass data table in mysql with python's MySQLdb lib,
something frustrated me. I could't find any function like datareader,
which yield one row by recording rows' anchor ,after each time I
invoked 'read()' in a loop.fetchall or fetchmany just fetched all data
in once, which take so much memory when meeting one mass data
table.
  Is anybody know that function or other lib similar to MySQLdb ?
thanks!