Author here. They are very independent. In short: Cubes is OLAP framework for abstracting aggregate queries on top of a datastore, mostly through SQL. You define a so called multi-dimensional model – how the analysts see the world, and cubes knows how to project it to underlying data structures, preferably star or snowflake table schemas.<p>Bubbles was meant to be data integration library (also known as ETL) – get data from multiple sources, transform them and produce tables that are more suitable for further analysis or reporting.