Python组装 update

import LVDataBase

db = LVDataBase.LVDataBase()

res = db.doquery_dic("select * from action_inf")
sql  = ''
for i in res:
    flag_str = 'update action_inf  set '
    for key_item, value_item in i.iteritems():
        flag_str = flag_str + key_item + ' = ' + "'%s'" %str(value_item) + ','
    flag_str = flag_str + ") where action_id = '%s' ;" %i['action_id']
    print flag_str