BO and OLAP

general discussion
1

Hi All,
I know there are a lot of discussions on this topic, but I need to clear a few things.
I first learned BO and then went through some of the data warehousing presentations. There I cam across the term OLAP which circulated around terms which I had come across in BO before e.x. drill, slic & dice, cube, etc.

      What I want to know is that : Are these all concepts of OLAP?

Is BO an OLAP tool? If yes which one : ROLAP / MOLAP / HOLAP?

       This might have been repeated. I did search the forum also but could not find a thread which answered these clearly? Also I went through the sites mentioned, but it got confusing.
  • Akshay

akshay :india: (BOB member since 2004-02-05)

2

I’ll let the more experienced members contribute more detail, but here is how I understand it … at least as it relates to BusObj … relational database and OLAP are mutually exclusive as a data source.

A relational database can have a universe built to represent it, and using BusObj (results in a cube, slice and dice, automatic aggregation of measures, cross-tabs, drilling, and so forth), you can approach the functionality of OLAP.

True OLAP is its own data structure, and the OLAP engine provides the multi-dimensional capabilities (drill, etc.). BusObj simply has an interface to allow the use of that OLAP engine directly.

Simplistic explanation, since I have no experience with true OLAP data sources. Again, I’m hoping the more experienced BOB members can confirm / clarify / contribute more detail if needed.

Dwayne Hoffpauir :us: (BOB member since 2002-09-19)

3

I would say BO is a combination of ROLAP + DOLAP :wink:

Sridharan :india: (BOB member since 2002-11-08)

4

Hi,
Can you explain it a little more as why it is so?

akshay

akshay :india: (BOB member since 2004-02-05)

5

Hi Akshey,

the first thing’s to say is: Sridharan is quiet right.

So for the better understanding, let’s specify what’s what and really means.

OLAP
Known as the short form of Online-Analytical-Processing. As You mentioned right, things like slice&dice, cubes, pivoting, dill-up&drill-down.
In other words, this only describes what You want to do - in a first descibtion-step.
The seccond is, that OLAP also means, that the analyst uses his own business-language for his query- and anlalytical job. So the “naming” of those enteties he’s “looking” on is quiet different from those used within the “technical”-view of relational databases.

The main-aim of OLAP is the multi-dimensional view on data, basing on whatever DB.

ROLAP
That means Relational OLAP. Within a ROLAP inviroment the DB helds its data not in a multidimensional form, but in relational DBs. The Sence of multidimendionality is a simulation. So there are direct SQL-requests against relational DBs. Those DBs regulary use special data schemes, like Star- or Snow-Flake-Schemes.

MOLAP
Multidimensional OLAP. This is the “thing” which really stores data in multidimensional manner. That means that data are physically stored as multidimensional cubes.

HOLAP
This is the so named Hybrid OLAP.
The reason for this was the empirial knowlegde, that sometimes a sheer MOLAP is not very prolific for all business questions. So You get a combination of real MOLAP as one part and a real ROLAP as the other.

DOLAP
This only means Desktop OLAP. This most of the time describes a client (Desktop) which get’s it’s data from the database, most of the time relational DB’s, keeps those data offline and forms a OLAP-cube, with the a.m. features like drill… and so on.

I hope, that, at this point, it becomes clear, what I mentioned on top of my posting…
Sridharan is quiet right. :lol:

MJGrass :de: (BOB member since 2004-09-09)

6

A good website related to OLAP - I’m sure many of you have seen it before:

Regards,
Chris

cjweis (BOB member since 2003-10-02)