
Data Modeling for Azure Data Services
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Hubs and Links only contain keys. Hubs only contain the business keys of entities, not descriptive data of those entities. Links only contain foreign keys to Hubs or other Links, but again, no descriptive data. We do create the LoadDate
and Source
columns, but these are not real descriptive data of the entities or the relationships. We add Satellite tables to the main structure of the Data Vault as defined by the Hubs and the Links. Satellite tables, or just Satellites, contain the "real" data, the descriptive data. This, of course, includes non-unique data values such as product color.
A Satellite is a table containing detailed and historical descriptive data columns of a Hub or a Link. Figure 9.8 shows a Satellite:
Figure 9.8 – Satellite table
A Satellite has the following columns: