Introduction

I'm new to ArrangoDB and on a voyage of discovery, so here are my thoughts and understanding of the model

Data Model

Document model organised as JSON elements but stored in a binary format called VelocityPack.  A document contains zero or more attributes, each of these attributes having a value. A value can either be an atomic type, i. e. number, string, boolean or null, or a compound type, i.e. an array or embedded document / object. Arrays and sub-objects can contain all of these types, which means that arbitrarily nested data structures can be represented in a single document.

Documents are grouped into collections. A collection contains zero or more documents (collections are similar to tables in a RDBMS - the difference being that you must define a schema in a RDBMS, ArrangoDB is schema-less, this can present a problem when trying to determine how to query the DB without knowledge of what the links are).  Each Document can be structured uniquely - this lends itself to the schema-less model.