Although this abstraction is elegant and possibly sufficient for the purpose
of examining alternative strategies for view maintenance, it is sufficient enough
to describe the structure and contents of a data warehouse in real-world settings.
Vassiliadis, Quix, Vassiliou, and Jarke (2001) bring up the issue of data warehouse
operational processes and deduce the definition of a table in the data warehouse as
the outcome of the combination of the processes that populate it. This new kind of
definition complements existing approaches, since it provides the operational semantics
for the content of a data warehouse table, whereas the existing definitions give
an abstraction of its intentional semantics. Indeed, in a typical mediation scheme
one would pose a query to a ???virtual??? data warehouse, dispatch it to the sources,
answer parts of it there, and then collect the answers. On the contrary, in the case
of data warehouse operational processes, the objective is to carry data from a set of
source relations and eventually load them in a target (data warehouse) relation. To
achieve this goal, we have to (a) specify data transformations as a workflow and
(b) optimize and execute the workflow.
Data warehouse operational processes normally compose a labor intensive workflow
and constitute an integral part of the backstage of data warehouse architectures.
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