Dimensions with multiple attributes

  • Hi, relatively new to data-modelling data warehouses so bare with me.

    I have a Product dimension table that connects to my Sales Fact table.

    Sales want to report on the categories that the product fits into. There are multiple categories for each product.

    Am I supposed to duplicate entire rows in the Product Dimension for each category the product fits into or am I supposed to snowflake my current star schema with a ProductCategory dimension and link table between the two?

    I'm afraid that if I do the former then my Dimension table will become huge and if I do the latter then the model is not simple enough for me to hand over to end users.

    Any thoughts will be gratefully appreciated.

    Thanks

    Tim

  • "There are multiple categories for each product."

    That's unusual. Could you give an example? Normally, you have a category hierarchy (Category, Subcategory...)

  • There are two options:

    * just add extra columns to store the different catagories. Easiest solution by far, but the least flexible.

    * snowflake to a category dimension and add a bridge table in between. More difficult but very flexible.

    To meet the less tech savvy users in between, you could add a column "Primary category" to the product dimension. You could write simply queries where each product has only 1 category. People who know how to write SQL can use the bridge table to report on all categories.

    Need an answer? No, you need a question
    My blog at https://sqlkover.com.
    MCSE Business Intelligence - Microsoft Data Platform MVP

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