X-WACoDa - Data Warehousing Design and Advanced Engineering Applications - page 49

Figure 6. SMAIDoC architecture

of agents that collect or extract data ( DataAgent ),
structure and model them ( WrapperAgent ), trans-
late them and generate the corresponding XML
documents ( XML Creator ), and finally store the
obtained XML documents into a database ( XM-
L2RDBAgent ).
Then, UML2XML is a graphical interface that
helps users express their analysis requirements in
UML and outputs an XML document representing
the warehouse schema: dw-model.xml .
Finally, X-Warehousing generates the ware-
house's XML documents (Boussaïd et al. , 2006).
XWarehousing inputs the complex data that
have been formated in XML by SMAIDoC, as
well as the user analysis requirements produced
by UML2XML. Its architecture is made of two
modules (Figure 7):

1. A loader module that loads user require-

ments and XML data source schemas, and
then transforms them into attributes trees
(Golfarelli et al. , 2001);

2. A merger module that merges these attribute

trees into one final attribute tree representing
the warehouse schema. The merging process
operates through the application of fusion
functions (pruning and grafting).

Data Warehouse

X-Warehousing directly outputs XML documents
that form an XML data warehouse with respect to
our reference model. Fact data are stored in one or
several facts f . xml documents (several in the case
of a constellation schema). Dimension data are
stored, for each dimension d , in the dimension d .
xml document. Data exploitation is achieved

Figure 7. X-Warehousing architecture