example.createCriteria().andIdGreaterThan(4);
key = new PkonlyKey(null, 3);
int rows = mapper.updateByExampleSelective(key, example);
assertEquals(2, rows);
example.clear();
example.createCriteria().andIdEqualTo(5).andSeqNumEqualTo(3);
rows = mapper.countByExample(example);
assertEquals(1, rows);