The Data Vault Model consists of three main parts along with hubs, there are links and sattellites.
These are the so called skeletton of the model.
A Hub is used to store business keys, which also may be composite.
Hubs are also not allowed to have foreign keys and it always should be tried to integrate business keys into single Hubs.
Hereby it is important that they represent the same grain and semantic definition.
Hubs are a unique list of business keys, surrounded with further metadata elements.
These meta data elements are information which describes the business keys in more detail:
* Sequence or Hash Key: unique number to identify the data in the whole system * Load Date Time Stamp: timestamp which indicates the first date the key was loaded into the data warehouse * Record Source: this attribute describes from which source the data was loaded into the data warehouse\\
|SEQ||Sequence (Primary Key)||Data Vault 1.0|
|HKEY||Hash Key (on BK, is the PK)||Data Vault 2.0|
|LDTS||Load Date Timestamp||1.0 and 2.0|
|RSRC||Record Source||1.0 and 2.0|
|BK||Multiple Business Keys||1.0 and 2.0|
Business keys are connections, which indicate how the business cooperates and accesses information.
Therefore it is very important to have unique business keys. These keys are also used as secondary unique constraints in the Hub table.
One feature is that they are supposed to have meaning to the business.
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