Blog Archives

OBI’s Nested Aggregation > Ralph Kimball

Ok so I put a provocative title on this post for a reason.  This post will explore why some of Kimball’s concepts may be out dated when newer query generation or database capabilities are taken into account.  Specifically, I’m going to discuss the OBI concept of Nested Aggregation, also known as Dimension Based Aggregation, in detail.  Using this OBI Modeling technique you can relax a bit on one of the Kimball Dimensional Modeling rules.  I’ll show how it works in a simplified manner, plus identify some things to be careful with and how it does not alleviate you from doing real modeling work. Read the rest of this entry

Modeling Header & Details

Originally posted 3/16/2007

A common question I hear is about how to model & configure a Header-Detail scenario.  By saying header-details, we are referring to a transaction that is split over more than one granularity.  This is common modeling scenario such as Order & Order Line Item, Invoice & Invoice Detail, Agreement & Agreement Line Item, etc. Read the rest of this entry

Over Reliance on the RPD

Originally posted 12/15/2006

This is one of my more popular old posts from IT Toolbox, and it still holds perfectly true today.  I even added a few more sections on it to freshen it up a bit

One of the more common causes of problems with projects I see as a consultant is the over reliance on OBIEE instead of the Data Model ETL  Over the years I’ve been brought into a few red accounts when I was at Siebel and Metricsphere where the RPD configuration was way too complicated.  We must remember that Analytics is a tool, and all tools have limitations.  Push too hard on the tool, and it will break, or almost as bad, it will become an unmanageable, unmaintainable mess that will break eventually. Read the rest of this entry