What is degenerate dimensions
Definition of degenerate dimensions is ranked by Ralph Kimball. Generally speaking, the foreign keys in the fact table correspond to a dimension, and the dimensional information is mainly stored in the dimension table; but the degraded dimension is only a column in the fact table, and the relevant information of this dimension is in this column, no dimension Associated it. For example: invoice number, serial number, etc.
So what role is there?
1. Degraded dimensions have a variety of operations, such as: on volume, slice, cutting, etc.
2. If there is a degenerate, the process of ETL will become easy.
3, it can make Group By to become faster
