Replication and External Data - PostgreSQL: Up and Running - page 189

Next, establish at least one user for your FDW. All users that connect to your server
should be able to access the Google search server, so here we create one for the entire
public group:
CREATE USER MAPPING FOR public SERVER www_fdw_server_google_search ;
Now create your foreign table, as shown in Example 10-4 .
Example 10-4. Make a foreign table from Google
CREATE FOREIGN TABLE www_fdw_google_search (
q text ,
GsearchResultClass text ,
unescapedUrl text ,
url text ,
visibleUrl text ,
cacheUrl text ,
title text ,
content text
) SERVER www_fdw_server_google_search ;
The user mapping doesn't assign any rights. You still need to grant rights before being
able to query the foreign table:
GRANT SELECT ON TABLE www_fdw_google_search TO public ;
Now comes the fun part. We search with the term New in PostgreSQL 9.4 and mix in
a bit of regular expression goodness to strip off HTML tags:
SELECT regexp_replace ( title , E '(?x)(< [^>]*? >)' , '' , 'g' ) As title
FROM www_fdw_google_search where q = 'New in PostgreSQL 9.4'
LIMIT 2 ;
Voilà! We have our response:
title
----------------------------------------------------
What's new in PostgreSQL 9.4 - PostgreSQL wiki
PostgreSQL: PostgreSQL 9.4 Beta 1 Released
(2 rows)