public Map<String, String> userJobList(int uid) {
		Map<String, String> jobList = new HashMap<String, String>();
		// fetch related data from database
		String sql = "select u_clubs,u_clubs_level from user where uid=" + uid;
		// parse the data
		Map<?, ?> map = (Map<?, ?>) (Object) querySql(sql).get(0);
		String clubData = map.get("u_clubs").toString();
		String jobData = map.get("u_clubs_level").toString();
		
		if (clubData.equals("") || jobData.equals(""))		// well, in case...
		{	System.out.println("NULL");return null;}
		System.out.println("clubData:" + clubData);
		int[] clubs = format.transformString2IntegerArray(clubData, ",");
		int[] jobs = format.transformString2IntegerArray(jobData, ",");		// ATTENTION: mutilated job is not ready
		for (int i=0; i<clubs.length; i++) {
			// fetch different clubs' title
			sql = "select club.cid,job.jo_name" +
					" from club inner join job on job.joid=" + jobs[i] + " where club.cid=" + clubs[i];
			map = (Map<?, ?>) (Object) querySql(sql).get(0);
			// push in
			jobList.put(map.get("cid").toString(), map.get("jo_name").toString());
		}
		return jobList;
	}