Was the data warehouse built according to the Data Vault scheme — did you also develop and support it? Did you add hubs and links manually?

Yes, I have worked with Data Vault in practice. During the support and development of the data warehouse, I had to manually add new hubs and links, especially when new business entities or relationships between them appeared. I usually started with analyzing data sources, identifying key business objects for hubs, and then creating corresponding tables with surrogate keys and attributes. For links, I connected hubs, reflecting relationships between entities, considering timestamps to track changes.

Example of creating a hub and link in SQL:

-- Creating a hub for customers
CREATE TABLE hub_customer (
  customer_key INT PRIMARY KEY,
  customer_business_key VARCHAR(50) NOT NULL,
  load_date TIMESTAMP NOT NULL,
  record_source VARCHAR(50) NOT NULL
);

-- Creating a link between customer and order
CREATE TABLE link_customer_order (
  customer_order_key INT PRIMARY KEY,
  customer_key INT NOT NULL,
  order_key INT NOT NULL,
  load_date TIMESTAMP NOT NULL,
  record_source VARCHAR(50) NOT NULL,
  FOREIGN KEY (customer_key) REFERENCES hub_customer(customer_key),
  FOREIGN KEY (order_key) REFERENCES hub_order(order_key)
);

This approach provides flexibility and scalability for the warehouse, as well as makes it easy to track the history of changes.