code: private int save(Object po, String autoGeneratedColumnName) throws Exception {
  
  		SqlParamsPairs sqlAndParams = ModelSqlUtils.getInsertFromObject(po);
  
  		//动态切换库名
  		String sql = sqlAndParams.getSql();
  		
  		return getProxy().insert(sql, sqlAndParams.getParams(), autoGeneratedColumnName);
  	}
docs: 保存对象并返回自增长主键的快捷方法
  
  @param po
  @param autoGeneratedColumnName
  自增长的主键的列名 比如 user_id
  @throws Exception