Satellites
The Hubs and Links form the structure of the model, but have no temporal attributes and hold no descriptive attributes. These are stored in separate tables called Satellites. These consist of metadata linking them to their parent Hub or Link, metadata describing the origin of the association and attributes, as well as a timeline with start and end dates for the attribute. Where the Hubs and Links provide the structure of the model, the Satellites provide the "meat" of the model, the context for the business processes that are captured in Hubs and Links. These attributes are stored both with regards to the details of the matter as well as the timeline and can range from quite complex (all of the fields describing a clients complete profile) to quite simple (a satellite on a Link with only a Valid-indicator and a timeline).
Usually the attributes are grouped in Satellites by source system. However, descriptive attributes such as size, cost, speed, amount or color can change at different rates, so you can also split these attributes up in different Satellites based on their rate of change.
All the tables contain metadata, minimally describing at least the source system and the date on which this entry became valid, giving a complete historical view of the data as it enters the data warehouse.
Read more about this topic: Data Vault Modeling, Basic Notions
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