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  1. #1
    Join Date
    Apr 2012

    Unanswered: Date and Time Dimensions

    Hope I find you well guys. I am new to data warehousing and I need to create time and date dimensions for the warehouse I am implementing. Can anyone help me on how to do this, my ETL tool is IBM InfoSphere Warehouse. The data source, execution and target databases are all on DB2.

  2. #2
    Join Date
    Feb 2008
    ... I need to create time and date dimensions
    My questions are...

    (1) Why "need to create ... dimensions"?
    I don't know about "create dimensions" so much, so I asked this question.
    I thought that to make an index on the column(or an index having the column as the first column) would be enough for performance.

    (2) What were differences between "to create time and date dimensions" and "to create other than time nor dimensions"?

  3. #3
    Join Date
    Jan 2007
    Jena, Germany
    Dimension tables in warehouses are typically used in "star schemas" or "snowflake schemas". You may want to read up on those.

    Basically, a time dimension is a regular table with a synthetic primary key column (which is then referenced from the fact table). Whichever columns you have in your dimension table depends on your requirements. You may have separate columns for year, month, day, week, quarter, or you may have just a single column of data type DATE.
    Knut Stolze
    IBM DB2 Analytics Accelerator
    IBM Germany Research & Development

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