[ACP01] Dimension Hierarchies Design from UML generalizations and aggregations
Conférence Internationale avec comité de lecture :
Int. Conf. on Conceptual Modeling (ER2001),
January 2001,
pp.15,
motcle:
Résumé:
Data for decision-making applications are based on dimensions,
such as time, customer, and product. These dimensions are naturally related
by hierarchies. Hierarchies are crucial to multidimensional modeling.
Defining hierarchies using star or snowflake schemas can be misleading,
since they are not explicitly well-modeled. However, deriving them from
conceptual UML or ER schemas is a non-trivial task since they have no
direct equivalent in conceptual models. This paper focuses on the definition
of multidimensional hierarchies. We present and illustrate rules for defining
multidimensional hierarchies from UML schemas, especially based on
aggregation and generalization hierarchies. The definition of hierarchies is
part of a data warehouse design method based on the three usual modeling
levels : conceptual, logical, and physical. The conceptual schema is based
on the UML notation. The logical schema is represented using a unified
pivot multidimensional model. The physical schema depends on the target
ROLAP or MOLAP tool.