code: public void getModelGeneratedKey(Model<?> model, PreparedStatement pst, Table table) throws SQLException {
  		String[] pKeys = table.getPrimaryKey();
  		ResultSet rs = pst.getGeneratedKeys();
  		for (String pKey : pKeys) {
  			if (model.get(pKey) == null || isOracle()) {
  				if (rs.next()) {
  					Class<?> colType = table.getColumnType(pKey);
  					if (colType != null) {	// 支持没有主键的用法，有人将 model 改造成了支持无主键:济南-费小哥
  						if (colType == Integer.class || colType == int.class) {
  							model.set(pKey, rs.getInt(1));
  						} else if (colType == Long.class || colType == long.class) {
  							model.set(pKey, rs.getLong(1));
  						} else if (colType == BigInteger.class) {
  							processGeneratedBigIntegerKey(model, pKey, rs.getObject(1));
  						} else {
  							model.set(pKey, rs.getObject(1));	// It returns Long for int colType for mysql
  						}
  					}
  				}
  			}
  		}
  		rs.close();
  	}
docs: 用于获取 Model.save() 以后自动生成的主键值，可通过覆盖此方法实现更精细的控制
  目前只有 PostgreSqlDialect，覆盖过此方法