I have a simple home-rolled CMS built on PHP using CakePHP that manages content in various tables that is, pretty much, all related through relational links in the RDBMS. I want to move to a CMS that supports versioning, user admin, themes, etc., etc - all the good stuff that Drupal offers.
I understand, mostly, how to use Drupal to get the data in to Drupal, organising the data using my own Content Types and the Entity Reference module to emulate the relations that I had in my RDBMS schema.
My problem is that I need to get the data out of Drupal with a view to extracting a lump of data (a group / 'web' of related content of different content that follows down the rabbit hole of all references between Entity Reference instances). I need to extract that data set in XML / JSON / SQLLite or similar in my 'nice' schema - I don't want or need all of the Drupal specific stuff about versions, users, edits, etc - just a snapshot of all (or some subset specified by some select-kind-of-criteria, like the ID of a node) the content so that I can recreate an instance of the data like I used to have in my original, hand-rolled RDBMS.