CenterGraph is document oriented. This means that most things will be centered around documents. This enables the offline capabilities. This also means that when you query the result can ony be a count or a list of document identifiers.
Using documents makes it possible to switch to an offline datastore when there is no connection available. This offline datastore loads all the documents and on top of that RDF data you can than do offline queries. Because of this mechanism queries for online and offline work exactly the same.
A document in CenterGraph is a named RDF graph.