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Thread: creating a data warehouse

  1. #1
    Join Date
    Oct 2007
    Posts
    11

    Default creating a data warehouse

    Hi.

    I need to create a data warehouse.

    My data base are 4 xls files, and i would like to know how extract this data and load it into the dimension and fact tables... i've been using the combination look/up tool, but i have some problems with the technical key field, because i want to choose one of the xls files field as a key, but the program makes me create a new one.

    Well, any sugestion will be good.
    Thanks.

    ps: im from Chile, so, if you dont understand something, please let me know.

  2. #2
    pstoellberger Guest

    Default

    the technical key must be a new field in the DB. its a surrogate key and only needed if you want slowly changing dimensions (historicized dimensions)

    if you don't need that you can use e.g a table output for loading the dimension data into the datawarehouse

    you can use the excel input for loading the data from the excel

    -paul

  3. #3
    Join Date
    Oct 2007
    Posts
    11

    Default

    Ok, im gonna try that... thanks for answering so soon pstoellberger.

  4. #4
    Join Date
    Feb 2009
    Posts
    296

    Default

    I urge you to use the surrogate key. Just image some progress in your company and someone starts replacing those Excel files with databases. Your input key is going to change in meaning. If you don't go for a surrogate key you will have problems.

    The natural key may very well be from your input but you should make sure you're using surrogate keys on all dimension elements.
    Fabian,
    doing ETL with his hands bound on his back

  5. #5
    Join Date
    Jan 2006
    Posts
    245

    Default

    I totally agree with fabianS. +1 to use surrogate keys and not natural keys

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