Degenerated Dimension is a dimension KEY without corresponding dimension. EXAMPLE:

In the PointOfSale Transaction FACT table, we have:

Date Key (FK), Product Key (FK), Store Key (FK), Promotion Key?(FP),?and POS Transaction Number?? Date Dimension corresponds to Date Key, Production Dimension corresponds to Production Key. In a traditional parent-child database, POS Transactional Number would be?the key to the transaction header record that contains all the info valid for the transaction as a whole, such as the transaction date and store?identifier.?But in this?dimensional model, we have ALREADY extracted this info into other dimension. Therefore, POS Transaction Number?looks like a dimension key in the fact table but does not have the corresponding dimension table.

Therefore, POS Transaction Number is a degenerated dimension.

Degenerated Dimension is a dimension key without corresponding dimension. Example:

In the PointOfSale Transaction Fact table, we have:

Date Key (FK), Product Key (FK), Store Key (FK), Promotion Key?(FP),?and POS Transaction Number?? Date Dimension corresponds to Date Key, Production Dimension corresponds to Production Key. In a traditional parent-child database, POS Transactional Number would be?the key to the transaction header record that contains all the info valid for the transaction as a whole, such as the transaction date and store?identifier.?But in this?dimensional model, we have already extracted this info into other dimension. Therefore, POS Transaction Number?looks like a dimension key in the fact table but does not have the corresponding dimension table.

Therefore, POS Transaction Number is a degenerated dimension.