用到以下函数:
1.connectby
2.crosstab
3.dblink
4.dblink_build_sql_delete
5.dblink_build_sql_insert
6.dblink_build_sql_update
7.dblink_cancel_query
8.dblink_close
9.dblink_connect
10.dblink_connect_u
11.dblink_current_query
12.dblink_disconnect
13.dblink_error_message
14.dblink_exec
15.dblink_fetch
16.dblink_get_connections
17.dblink_get_pkey
18.dblink_get_result
19.dblink_is_busy
20.dblink_open
21.dblink_send_query