code: public int update(Entity entity) throws SQLException {
  		if (CollectionUtil.isEmpty(entity)) {
  			return 0;
  		}
  		entity = fixEntity(entity);
  		Object pk = entity.get(primaryKeyField);
  		if (null == pk) {
  			throw new SQLException(StrUtil.format("Please determine `{}` for update", primaryKeyField));
  		}
  
  		final Entity where = Entity.create(tableName).set(primaryKeyField, pk);
  		final Entity record = (Entity) entity.clone();
  		record.remove(primaryKeyField);
  
  		return db.update(record, where);
  	}
docs: 更新
  @param entity 实体对象，必须包含主键
  @return 更新行数
  @throws SQLException SQL执行异常