What type of key is the ProductKey in a data warehouse dimension table?

In a data warehouse dimension table, the ProductKey is considered a surrogate key. Surrogate keys are unique identifiers for each record in the dimension table that are not derived from any business data. They are typically implemented as generated numbers or sequential identifiers, and serve the primary purpose of establishing unique identities for each row of data within the context of the data warehouse.

Using surrogate keys like ProductKey provides several advantages. It allows for easier management of keys when source systems change, simplifies the integration of data from multiple sources, and enhances query performance by enabling faster joins between fact and dimension tables. Surrogate keys are also beneficial for maintaining historical accuracy, as they can help manage slowly changing dimensions without affecting the underlying business logic.

The distinction of using a surrogate key signifies that the ProductKey does not carry any business meaning, unlike business keys or alternate keys, which might represent actual entities or relationships in the business context. This design approach helps maintain data integrity and provides a clean separation between the operational and analytical aspects of data.