With the advent of Data Vault 2.0, which adds architecture and process definitions to the Data Vault 1.0 standard, Dan Linstedt standardized the Data Vault symbols used in modeling. Based on these standardized symbols, the Visual Data Vault (VDV) modeling language was developed, which can be used by EDW architects to build Data Vault models. The authors of the book “Building a Scalable Data Warehouse”, who are the founders of Scalefree, required a visual approach to model the concepts of Data Vault in the book. For this purpose, they developed the graphical modeling language, which focuses on the logical aspects of Data Vault. The Microsoft Visio stencils and a detailed white paper are available on www.visualdatavault.com as a free download.
Hubs in Visual Data Vault
Business keys play an important role in every business, because they are referenced by business transactions and relationships between business objects. Whenever a business identifies and tracks business objects, business keys are used throughout business processes. This is one of the reasons why Data Vault is based on the business keys. In Data Vault models, business keys are stored in hub entities. The challenge is to identify the business keys which represent a business object uniquely. That can be just one business key, but also a composite key or a smart key. The first image shows a hub with only one business key attribute: