Data engineering·Modelling for analysis
the order number sits on the fact table with no dimension table behind it, because there is nothing else to say about an order number.
Degenerate dimension
Also calleddimension without a table
A dimension attribute kept on the fact row because it has no other attributes worth a table of its own — typically a transaction identifier used for grouping line items. It looks like a modelling mistake and is not: creating a one-column dimension table for it would add a join and describe nothing. Naming it stops a reviewer from insisting on a table that would be pure ceremony.