 OLAP
(MOLAP, ROLAP, HOLAP, WOLAP, DOLAP)
What
is OLAP? |
| OLAP, On Line Analytical
Processing, means the area of analysing information with multi-dimensional techniques
for Management Information purpose. (OLAP versus OLTP; Online Transactional
Processing, where the transactions are key object of interst). OLAP is more or less
a technique incorporated in software tools. It is used by information analists
(controllers, data analysts, managers) for making financial or marketing related analyses.
Typically these application work with al big amount of structured information. Structured
means that the information is structered towards the needs of the users e.g. Sales related
to Products, Region, Sales Force, Channel and Time; the so-called 'dimensions'. Within
dimensions there different levels of information available. Aggregation levels and detail
levels of information most times called hierarchies. Typicaly
for OLAP environments are the multi-dimensional cubes with 'dice and slice' possibility to
analyse the information from different perspectives. (see logo left upper corner). |
| MOLAP |
Multidimensional
OLAP |
The
MOLAP environment consists of a multi-dimensional cube with all possible perspectives
precalculated. Therefore MOLAP applications do have a high performance. At the same time
the need a lot of disk capacity to store all the precalculated figures. |
| ROLAP |
Relational
OLAP |
The
ROLAP envirenment consist of a relational database with a OLAP query engine. Every
information need is calculated on the fly by the OLAP query engine. therefore ROLAP
mosttimes has a slower performance. Never the less, it needs less disk space to store the
data. |
| HOLAP |
Hybrid
OLAP |
The
HOLAP environment consists of both a relation database and a preconfigured multi-dimension
cube. Most times you can be flexible in keeping information in the relational database
and/or the preconfigured multi-dimensional cube. |
| WOLAP |
Web
enabled OLAP |
The
frontend user can access the OLAP application through a web browser. |
| DOLAP |
Desktop
OLAP |
All the
OLAP functionality can be performed on a Desktop PC. Most other OLAP mentioned here are
client-server and/or server based database applications. |
Why OLAP?  |
| To have the ability
to logically organize data hierarchically in multiple dimensions for users to quickly create,
calculate, and analyse complex data relationships. |
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