Rule 3: Linking classes
Each class Ci built from attribute at level i of a
hierarchy h, is connected via a composition link
to the class C
i-1
, of the same hierarchy, if any.
Rule 4: Transforming facts into associations
A fact table is transformed into an association
linking the finest level classes derived from its
dimensions. Measures of the fact become
attributes of the association.
Note that all of the above four rules apply only to
non-date dimension. Rule 5 deals with date
dimension.
Rule 5: Transforming date dimension
A date dimension is integrated into each of its
related fact classes as a full-date, i.e., detailed
date.
6 RELATED WORK AND
CONCLUSION
There are several proposals to automate certain tasks
of DW design, c.f., (Cabibbo, 1998), (Golfarelli,
1998), (Hahn, 2000), (Peralta, 2003), (Sergio, 2003)
(Moody, 2000), (Marotta, 2002) and (Hahn, 2000).
Other works pertinent to automated DW design
mainly focus on the conceptual design, c.f.,
(Hüsemann, 2000) and (Phipps, 2002) which
generate the conceptual schema from an E/R schema
of the source database. However, these works do not
focus on a conceptual design methodology based on
users’ requirements and are, in addition, limited to
the sources described as E/R.
The work presented in this paper is a step towards
the automatic construction of DW schemes. More
precisely, it defined an approach that generates
automatically the DM schemes from precisely
specified OLAP requirements. Then, it showed how
the DW schema can be generated systematically.
We are currently optimizing the generation of DM
schemes from OLAP requirements. In addition, we
are verifying the completeness of the DM to DW
schema transformation rules. We are also working
on how to identify specific ontology for DM/DW
design.
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