e., surrogate keys with hierarchy semantics). Moreover, fact table
physical organizations such as the CUBE File exploit h-surrogates to provide physical
data clustering w.r.t the dimension hierarchies, resulting in a reduced I/O fact
table access. Finally, the exploitation of the hierarchy semantics that h-surrogates
convey can lead to efficient query optimization techniques such as the hierarchical
pregrouping transformation.
The abstract processing plan can be easily incorporated in a DBMS provided that a
hierarchical clustering-preserving fact table organization is supported. For example
the methods introduced in this chapter have been fully implemented in the commercial
relational DBMS TransBase HyperCube?® (TransBase HyperCube?®, 2005),
which utilizes the UB-tree (Bayer, 1997) as a fact table primary organization.
References
Bayer, R. (1997). The universal B-tree for multi-dimensional indexing: General
concepts. Proceedings of the Worldwide Computing and Its Applications,
International Conference, Tsukuba, Japan (pp. 198-209).
Chan, C. Y., & Ioannidis, Y. (1998). Bitmap index design and evaluation. Proceedings
of the ACM SIGMOD International Conference on Management of Data,
Seattle, WA (pp. 355-366).
Chaudhuri, S., & Dayal, U. (1997). An overview of data warehousing and OLAP
technology. SIGMOD Record, 26(1), 65-74.
Karayannidis, N.
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