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  1. #1
    Join Date
    Mar 2004
    Posts
    2

    Unanswered: Shared Dimensions - OLAP

    Hi,
    I have noticed the the cubes that we have here use shared dimensions.
    For almost all cubes(5-6) there are at least 4-5 common dimensions.
    According to what I have been preached so far, the shared dimensions are so that you can reuse them. That is not what is practised here.
    for example.
    cube1 has somedim1, dim2_c1, dim3_c1...
    cube2 has xyzdim1_c2,xyzdim2_c2,dim3_c2..

    dim3_c1 and dim3_c2 are the same dimensions, one for each cube.
    I don't know if I am missing something. Shouldn't the use the same dimensions? Could there be any reason for this.
    pls. advice.

    TIA

  2. #2
    Join Date
    Feb 2004
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    Provided Answers: 54
    This happens pretty often in a warehouse where competing factions "own" different cubes. Instead of creating an overall cube structure to make things simpler for everyone, each group uses the structure that is simplest for them. This allows everyone as much freedom as possible, and grossly degrades the overall usefullness of the warehouse!

    -PatP

  3. #3
    Join Date
    Mar 2004
    Posts
    2

    Cubes on views too

    Thanks Pat, for the reply.
    Also another wierd thing is the cubes are on views. That is some of the dimensions are on views with join conditions. I thought even this will be poor performing. What do you think on this. How can views be avoided?

    TIA

  4. #4
    Join Date
    Feb 2004
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    15,579
    Provided Answers: 54
    If you mean the the source (OLTP) data for the cube (OLAP) data is from a view, this adds some overhead but it isn't a show-stopper. It all depends on how efficiently the views are coded.

    If you mean that OLAP users are accessing the cubes via MDX based views, this is perfectly normal in my opinion.

    -PatP

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