MongoDB in PHP, Java, and C - MongoDB in Action - page 273

<< "attrs" << BSON( "lastVisited" << DATENOW << "pingtime" << 20 ) );
cout << "Initial document:n" << doc.jsonString() << "n";
conn.insert( "crawler.sites", doc );
cout << "Updating pingtime...n";
BSONObj update = BSON( "$set" << BSON( "attrs.pingtime" << 30) );
conn.update( "crawler.sites", QUERY("_id" << doc["_id"]), update);
cout << "After update:n";
auto_ptr<DBClientCursor> cursor;
cursor = conn.query( "crawler.sites", QUERY( "_id" << doc["_id"]) );
cout << cursor->next().jsonString() << "n";
cout << "Number of site documents: " <<
conn.count( "crawler.sites" ) << "n";
cout << "Removing documents...n";
conn.remove( "crawler.sites", BSONObj() );
return 0;
}