What is the purpose of surrogate keys in a slowly changing dimension?

Surrogate keys serve primarily to uniquely identify records within a database, particularly in slowly changing dimensions (SCDs) in data warehousing. This uniqueness allows for each record to be associated with a specific version of data without being affected by changes in attributes that may occur over time.

In the context of slowly changing dimensions, surrogate keys help manage different states of the same entity. For instance, when a customer's information changes, rather than overwriting the existing record, a new record with a new surrogate key can be created. This approach preserves the historical context of the data while ensuring that each record can be distinctly referenced.

Through their unique identification capabilities, surrogate keys allow for accurate relationships and queries in the data warehouse, especially when historical tracking is necessary. Thus, while maintaining historical data is also a goal of slowly changing dimensions, the fundamental role of surrogate keys is to provide a unique identifier for each record.