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Thread: Question on Schema Design

  1. #1
    Join Date
    Apr 2011

    Default Question on Schema Design

    Hi everyone,

    I have a dimension called Product. where I support a hierarchy of

    ProductID   Company     Product         Model
    1           Apple       unspecified     unspecified
    2           Apple       Ipod            4G
    3           HP          Pavillion       m9020n
    4           HP          unspecified     unspecified
    However, some of the facts in the fact table specify values at a level
    higher in the hierarchy, like a product without a model, or the company
    without the product or the model. A solution to this problem I think
    would be to add a value of unspecified for the product and model that were
    not specified, but I am wondering if there could be a problem in rolling
    up facts that have a value of unspecified for both Product and Model. I am not
    very experienced in this star schema design stuff, I just want to know if you
    see a potentiall problem of filling in unspecified value when I don't know the value at
    a certain level of the hierarchy?

  2. #2
    Join Date
    Mar 2011


    Hello flethuseo,

    I'm also new with modelling star schema's, but what I understand from it, is that when you have an additive on an higher level of detail, you should probably create a seperate facttable.

    If this is not what you want to do, you might want to create a view perhaps ?
    If there is no obvious problem during development. I can imagine that your data might get displayed wrong, but other than that the design is just faulty (I guess).

    Do correct me if I have this wrong ...

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