Historical Data

The historical data layer contains data stores that hold all data from a certain point in the past (for example, the start of the company) up until now. In most cases, this data is considered to be important to run a business, and in some cases, even vital for its existence. For example, the historical data layer of a newspaper agency contains sources, reference material, interviews, media footage, and so on, all of which were used to publish news articles. Data is stored in blobs, file shares, and relational tables, often with primary and foreign keys (enforced by the infrastructure or in software). The data can be modeled to a standard such as a data vault to preserve historical information. This data layer is responsible for keeping the truth, which means it is highly regulated and governed. Any data that is inserted into one of the tables in this layer has gone through several checks, and metadata is stored next to the actual data to keep track of the history and...