Database Reference
In-Depth Information
Fig. 12.1 Cubism as
example of decomposition
of structures in small
building blocks
(Pablo Picasso, Les
Demoiselles d'Avignon,
1907)
One may ask: Why are we interested in a data warehouse-related standard like
CWM? Isn't the realtime analytical approach promoted in this topic the complete
antipode to data warehousing? This is definitely true. However, CWM is useful
because it can describe highly complex metadata of almost all types of data storage.
We have emphasized before that basis transformations are extremely important, not
just in modern mathematics but - in a wider sense - in many other areas such as
computer science. Similar to realtime analytics, which is becoming a key concept
for data analysis, we believe that basis transformations will become central for data
processing, including storage, comparison, and exchange of data. For this reason,
it was selected for XELOPES. To put it simply, we believe that comprehensive
metadata handling is of central importance for business intelligence. Therefore,
we will introduce CWM here although it is not directly related to realtime analytics.
CWM is one of the most abstract IT standards at all. Like in cubism Braque and
Picasso tried to decompose all images into a small set of geometric forms (most
notably cubes), CWM breaks down the IT structure of whole enterprises into
smallest atoms of a minimum number (UML-like classes) (Fig.
12.1
).
We will give a short introduction into the fascinating world of CWM only. For a
comprehensive description of data warehouse principles, we refer to [In96,
Kim96]. Our introduction to CWM is based on [PCTM02, PCTM03] which
explains the standard in all details.
As we already mentioned, CWM is a quite complex standard and requires knowl-
edge from other OMG standards likeMOF, XMI, UML, andMDA. Especially, CWM
is described in terms of the MOF (Meta-Object Facility) meta-metamodel. MOF, in
turn, leverages concepts from UML (Unified Modeling Language) for the description
of metamodels. Therefore, CWM uses UML for description and modeling and is
platform independent.
