Postgresql 恢复数据库值

我有 postgresql 数据库。我的表名是tblvoippolicy. 现在，问题是我错误地从表中删除了一些记录。当我使用以下命令获取数据文件时。

select * from pg_class where relname = 'tblvoippolicy' ; I get the following result

    relname    | relnamespace | reltype | relowner | relam | relfilenode | reltablespace | relpages | reltuples | reltoastrelid | reltoastidxid | relhasindex | relisshared | relkind | relnatts | relchecks | reltriggers | relukeys | relfkeys | relrefs | relhasoids | relhaspkey | relhasrules | relhassubclass | relacl 
---------------+--------------+---------+----------+-------+-------------+---------------+----------+-----------+---------------+---------------+-------------+-------------+---------+----------+-----------+-------------+----------+----------+---------+------------+------------+-------------+----------------+--------
 tblvoippolicy |        17234 |  407227 |      100 |     0 |      407226 |             0 |        0 |         0 |             0 |             0 | t           | f           | r       |        8 |         0 |           0 |        0 |        0 |       0 | t          | t          | f           | f              | 

现在，当我使用 cat 将该数据查看到数据库的数据文件中时/var/pgsql/data/base/17230/407226。我得到以下结果。

[root@manage upload]# cat /var/pgsql/data/base/17230/407226
ôu\"(Ô  Ÿà Ÿà¨žð8žàÔÈM ï¡test EC250
@%
ÿ10.106.1.228Q   ï–BEC200_Post_250      EC200
ú%
ú10.106.1.228?   ï”BBS_Service_Pre_250bs_service_1
@&
ú10.106.1.2286   ï’BEC200_Pre_500       EC200
@&
ô10.106.1.228+   ïBEC200_Pre_250       EC200
@&

我无法理解所描述的值，我想恢复从表中删除的记录，我怎样才能取回这些记录？