Comparison
Data vaultvsDimensional modelling
Data vault
the raw layer is split into keys, relationships and attributes as three kinds of table, and nothing is ever updated or deleted.
A modelling approach that separates business keys, the relationships between them and their descriptive attributes into hubs, links and satellites, all insert-only. It is built for auditability and for absorbing source change without refactoring: a new source adds satellites rather than altering existing tables. Nobody queries it directly — the table count is enormous — so it is always a raw layer with dimensional marts built on top, and adopting it without that second layer is the usual failure.
Full entry →Dimensional modelling
you stopped copying the application's tables into the warehouse and started shaping it around what happened and what it happened to.
Organising a warehouse around measurable events and the things that describe them, rather than around the shape of the source application. The point is that analysts write joins by hand under time pressure, so the schema is a user interface: predictable shapes beat clever ones. It has survived every generation of storage technology because the constraint it addresses — a human holding a query in their head — has not changed.
Full entry →