Blog Archives

Build Your Own Time Hierarchy

Every single BI system has a time/date/period/calendar hierarchy in it. If you use the BI Apps, it actually comes with 2 different tables for this purpose alone, along with a ton of OOB capability. However, when you are faced with a pure custom system from scratch, how do you build one? What does it look like? What sort of data should it have in it?

I’m going to lay out what a decent Time Hierarchy looks like from an OBI and data model perspective. From there I’ll then demonstrate how to actually build one yourself instead of relying on complex code. Along the way we’ll mix in some best practices and theory as well.

Your mileage may vary depending on the specifics of your system, but my goal is to make the design and building of your hierarchy take only 3 hours and last the lifetime of your project (or career). Read the rest of this entry

Degenerate Dimensions and Aggregates

An interesting topic came up recently on my latest project that I think is quite informative on how OBI works under the hood.  It involves how to model degenerate dimensional fields into OBI when there are aggregates present.  Individually each of these two topics are relatively well know with solutions for how to handle them, but when combined they can get pretty tricky.  This is especially true when you are using the BI Apps, which to a large degree still rely on the old method of manually mapping Time Series (Ago & ToDate) metrics (as opposed to the OBI 10.x + technique of Time Series functions) which require an explosion of Logical Table Sources (LTSs).

The core of this post concerns what do you do when some of your aggregates don’t have all of the degenerate fields that your base fact has?  What do you need to do to model them properly?  In the explanation I will shed a bit more light on how OBI “thinks” so that you too can model things properly the first time.

Read the rest of this entry

Making Dims & Facts Work Together

This is a very common RPD modeling question on IT Toolbox – it comes up every week it seems.  The problem is stated something like this:

I have 2 fact tables and 3 dimension tables.  One of the dimension tables doesn’t work with Fact #2 while the other 2 dimension tables work with both facts.  When I make a report with all 3 dimensions and both facts, Fact #2 is incorrect or missing. Read the rest of this entry

Achieving Good Performance With OBIEE

Originally posted 1/30/2007

How do you extract good performance from Oracle Business Intelligence (OBIEE)?  Are there any tool specific features that can be used to achieve better performance, or is it all about the backend?  This post will discuss some things to consider to make a page or report perform well; scalability is not included here. 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