Composite Natural ID

Hi

One of my dimensions has a composite natural id (Fund Code and Account Number), should I keep them separate in the dimension or concatenate them to form 1 natural id (e.g ."Fund Code-Account Number")

Regards

Tim

Separate. The basics of data modeling, storing one fact in one place, still hold true for dimensional models.

I always do both, for exactly the same reasons B&L pointed out. A natural key column is a different column that serves a different purpose than the Fund Code and Account Number. The purpose of the dimensional attributes (Fund & Account) is to provide query attribute values in reports, the purpose of the natural key column is to identify a row for surrogate key assignment purposes. The two may be different, paticularly if the dimension needs to support multiple disparate data sources.