In the data warehouse practice of extract, transform, load (ETL), an early fact or early-arriving fact,[1] also known as late-arriving dimension or late-arriving data,[2] denotes the detection of a dimensional natural key during fact table source loading, prior to the assignment of a corresponding primary key or surrogate key in the dimension table. Hence, the fact which cites the dimension arrives early, relative to the definition of the dimension value. An example could be backdating or making corrections to data.[3]


Procedurally, an early fact can be treated several ways:


  1. ^ "Kimball, Ralph. Design Tip #57: Early Arriving Facts. August, 2004" (PDF). Archived from the original (PDF) on 2007-10-12. Retrieved 2008-04-25.
  2. ^ Early Arriving Facts / Late Arriving Dimensions - LeapFrogBI
  3. ^ A gentle introduction to bitemporal data challenges - Roelant Vos