Oracle choices for Multidimensional Analysis

Here’s a quick assessment highlighting the main differences between Hyperion Essbase vs Oracle OLAP. Knowing that both products are now under the same ownership, I thought this should be archived before it gets completely outdated!

	Oracle Essbase	Oracle OLAP
What-is?	Standalone OLAP Server: separate to the Oracle database End-user focused, popular among business users as data access done via Excel Fully multidimensional OLAP engine with support of MDX and XML/A (rather than SQL)	Oracle OLAP option: in-database solution available in Oracle Enterprise (latest version 11g) Aggregation management solution for SQL-based BI applications Alternative to table-based materialized views solution, offering better query perf and fast incremental load A “real” multidimensional OLAP server paradigm and not a simple SQL relational hack
Underlying Technology	Storage Used: Server MOLAP proprietary storage Concept Used : Full OLAP capabilities leveraging business rules and names, with Dimensions, facts, hierarchies outlines, consolidation rules, write-back, annotate, calculated metric, etc Data Access : MDX access exposing full OLAP capabilities model, access API choices between Java and XML/A, Essbase query tools.	Storage Used: multidimensional arrays in DB Concept Used : Structured around business rules and naming, with Dimensions, facts, hierarchies, aggregation rules etc Data Access : Fast data access through “cells” (direct address) storing either details and summary data but leveraging SQL access mode OLAP Engine : advanced analytics like time series analysis, non-additive calculations, financial and statistical models
Key Benefits	Ø Renown and proven technology with important customer base and long history background Ø Use to power many of the Hyperion performance management applications	Ø Oracle Backend-Only Solution, no need for: a. external metadata b. exporting data c. separate server d. other backend application Ø Easier than Materialized View Solution, a. Avoid the complexity of choosing which MV to create and how many possibly creatable b. All summaries stored in a single OLAP multidimensional Cube c. CBO treats OLAP cubes as MVs: rewrites queries to access cubes transparently; refresh using MVs standard Ø Easy access to detail transaction as stored directly in Cube (transparently)
Drawbacks	Standalone application requiring: 1. Dedicated server hardware 2. External metadata, hence business rules, def.. duplications 3. Extraction and import of DWH data Currently, not fully integrated within Oracle infrastructure	Does not offer a full compliant multi-dimensional access to OLAP data : 1. No MDX, XML/A 2. No real OLAP-aware query, only support SQL language (olap extension) 3. No best suited for planning & forecasting tools

Martin

Personal Knowledge Management

I've always been looking for a tool that could simplify all notes I take to store and gather business knowledge I accumulate along my consulting activities.  This could even be leveraged  for other aspect of life for that matter, but for now my need is to optimize the knowledge acquisition and retention done when taking on new professional projects.

The level of cognitive load is directly linked to all the new information (principles, fact, rules, definition, etc.. ) that is  to be assimilated early on any new project inception.  Any method or tool helping me to optimize my knowledge acquisition and management could certainly be a big benefit for the project. 

The key spec I'm looking for in such a tool are:

1. must be flexible and easy to add new content without having to first organize and structure the content, the relationship among concept and taxonomy
2. must be light (must not "get in the way" ) and ideally available from the net and stored the info centrally
3. must easily allow for structuring, re-structuring the content (either through tag, hierarchy, taxonomy, etc...)
4. and obviously must be intuitive...

There are tools more oriented toward online collaboration which have been adapted for personal use: personal wiki ( e.g. twiki for personal, moinmoin personal).  But I find these too html-presentation oriented... my concern is to gather information not how should it be represented.

Although I did not yet find the optimal solution, I find the tools that falls into the area of  "mind-mapping" (e.g. theBrain, freeMind, thinkgraph) to offer good characteristics.   You are not too worried with how info is presented (since it pretty much follow a fix canvas) so you can fully dedicate yourself with the information content.  However, it does suffer from a few limitation:   volume content (I don't see collpasing/exploding thousands or more nodes), versioning and/or time-dependent information, ...

So until I find a better match, I will keep on relying on mind mapping software, and it always help when you can have a good open source and free version such as Freemind.   And for an online solution, there is also mind42.com.  

As an example, I just used it to gather some background knowledge on rules/best practices applicable when one wants to define data layer of aggregation in a typical data warehouse implementation relying solely on relational technology  (inspired from Mastering data warehouse aggregates).  Here is a partial view of this guideline (done with Freemind):

Here is the same guideline shown as a dynamic mind map :

Martin

Thesis

One of the reason why I'm holding this blog is to archive things I consider important enough to be kept in a longterm platform as I hope this one to be? A while back, I wanted to put online the thesis I wrote in the mid-90's... wow that sounds old! Being optimistic I though this would be a simple matter... it is not as if I wrote this with a typewriter requiring me to scan the entire document!  Word processor existed back then and I even used what was considered at the time the top of word processor: WordPerfect.

Well this wishful thinking was ignoring limitation of technology and its rapid obsolescence. When I consider what I ended up using to archive this important piece of work> not USB Flash drive, not CD , not DVD, not even Zip drive.. yes on those 3.5inch floppy disk: there was simply no chance of getting it back. I did manage to restore one diskette, but was less successful in reading and converting its format (of course I kept the files on their original WP 5.2 format ! ).

I bet nowadays most modern Universities preserve all post-grad work in their original digital content.

Anyway, enough allusion to my age, and here is the main content of this post> A full scan in pdf of my thesis dated back from 1994:

• [pdf] Part-1
• [pdf] Part-2
• [pdf] Part-3
• [pdf] Part-4
• [pdf] Part-5
• [pdf] Part-6
• [pdf] Annex & Biblio

Martin

p.s. Note that the paper copy I could get a hold on to still contains some minor editing to be done, so for the real final copy I'll need to get to McGill University.