Degenerate dimension

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In a data warehouse, a degenerate dimension is a dimension which is derived from the fact table and doesn't have its own dimension table. Degenerate dimensions are often used when a fact table's grain represents transactional level data and one wishes to maintain system specific identifiers such as order numbers, invoice numbers and the like without forcing their inclusion in their own dimension. The decision to use degenerate dimensions is often based on the desire to provide a direct reference back to a transactional system without the overhead of maintaining a separate dimension table.

[edit] See also

• data warehouse
• dimension table
• fact table
• measure (data warehouse)

[edit] External reference

Kimball University: Another Look At Degenerate Dimensions

[edit] References

• Kimball, Ralph et al (1998); The Data Warehouse Lifecycle Toolkit, p17. Pub. Wiley. ISBN 0-471-25547-5.

• Kimball, Ralph (1996); The Data Warehouse Toolkit, p. 100. Pub. Wiley. ISBN 0-471-15337-0.