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data-warehousedimensional-modeling

Usage of degenerate dimension in another fact table


How can I use degenerate dimension in another fact table?


Solution

  • By definition, a degenerate dimension is one where the attributes are kept with the measures in the fact table, and not in a dimension table.

    E.g, if you fact table is for retail sales, then the receipt number would be kept in the fact table, as otherwise you would be creating a dimension with a cardinality comparable to that of the fact table.

    So, I’m having some trouble understanding your question. How can the degenerate dim be kept on a different fact (sic) table? How would you join the two? If you have a key to join, then it’s not a degenerate dimension.

    If you mean “can I join two fact tables by a degenerate dimension attribute” the answer is probably not. The join would most likely be many to many, and it would involve joining two huge tables, which would be highly expensive.