stjärnschemat

Stjärnschemat is a Swedish term that translates to "star schema" in English. It is a data warehousing model used for organizing data to facilitate querying and analysis. The star schema is characterized by a central fact table surrounded by several dimension tables.

The fact table contains quantitative measures or metrics, such as sales revenue, units sold, or production output. These measures are typically numeric and can be aggregated for reporting purposes. The fact table also contains foreign keys that link to the dimension tables.

Dimension tables provide descriptive attributes that provide context to the measures in the fact table. For example, a dimension table for "products" might include attributes like product name, category, and brand. A "time" dimension table could contain attributes like year, month, day, and day of the week. Other common dimensions include "customer" and "location."

The structure of a star schema resembles a star, with the fact table at the center and the dimension tables radiating outwards. This simple and denormalized structure makes it efficient for query performance, as it reduces the number of table joins required to retrieve data. Analysts can easily slice and dice data by different dimensions to gain insights.

Star schemas are widely used in business intelligence and data warehousing applications due to their ease of understanding and efficient query capabilities. They are particularly well-suited for analytical queries that involve aggregations and comparisons across various business dimensions.