PgConnection
       makes a new connection to a backend database server.
PgConnection::PgConnection(const char *conninfo)
       The conninfo string is the same as for the underlying
       libpq PQconnectdb function.
      
       Although typically called from one of the access classes, a connection to
       a backend server is possible by creating a PgConnection object.
      
       ConnectionBad
       returns whether or not the connection to the backend server succeeded or
       failed.  
bool PgConnection::ConnectionBad() const
Returns true if the connection failed.
       Status
       returns the status of the connection to the backend server.
ConnStatusType PgConnection::Status()
Returns either CONNECTION_OK or CONNECTION_BAD depending on the state of the connection.
       PgDatabase
       makes a new connection to a backend database server.
PgDatabase(const char *conninfo)
       After a PgDatabase has been created it should be checked to make sure
       the connection to the database succeeded before sending
       queries to the object. This can easily be done by
       retrieving the current status of the PgDatabase object with the
       Status or ConnectionBad methods.
      
       DBName
       returns the name of the current database.
const char *PgConnection::DBName()
       Notifies
       returns the next notification from a list of unhandled notification messages 
       received from the backend.
PGnotify* PgConnection::Notifies()
       See PQnotifies in libpq for details.