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  1. #1
    Join Date
    Oct 2007
    Location
    Chicago, IL
    Posts
    82

    Help with Time dimension in data mart

    Designing a data mart for a messaging application. End users want to be able to display a histogram with the ability to show message volume in 5, 10, 15, 20, 25, 30, 1 hr intervals. In this case, would you populate the Time dimension with date/time data in 5-min. intervals. So each hour would be 12 records in the time dim. This results in approx. 105,120 rows per Year. I'm thinking of keeping the granularity to a Day in the time dimension, and just using an attribute in the fact table to note the time in the 5-minute increment.

    Any ideas?

    -a

  2. #2
    Join Date
    Apr 2002
    Location
    Toronto, Canada
    Posts
    20,002
    conceptually, it is six of one and a half dozen of the other

    (do that twice, and you gots a two-four )

    have you scoped out what kind of sql will drive the graphs both ways?
    rudy.ca | @rudydotca
    Buy my SitePoint book: Simply SQL

  3. #3
    Join Date
    Oct 2007
    Location
    Chicago, IL
    Posts
    82
    Just had a meeting...turns out, we need down to the minute granularity. I'll be keeping the granularity on the Time dimension to Day; and then storing the Hour and Minute as facts in the fact table.

    -a

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