Loading nodes from another Drupal database using Views
Consider looking at the Forena module. It can be used to query (not update) the data in other databases. Various DBMS formats are supported, such as another Drupal database also.

Forena is built of the idea of using SQL to get data out of a database and use XHTML and CSS to format it into web reports. For more details about Forena, 2 types of documentation are available:


Community documentation.
Documentation that comes with Forena, which you can access right after install and enable of the module. Checkout the demo site for an online example of the current:


Forena documentation - use the link 'Reporting documentation' or visit relative link /reports/help.
Forena samples - use the link 'Reporting samples' or visit relative link /reports/samples (these samples are fully functional, so make sure to experiment a bit with it, such as the drill downs available on the SVG Graph sample).



Disclosure: I'm a co-maintainer of Forena,
I hope this does not violate the site's policy on self-promotion.