The CUBE File requires the assignment of h-surrogates to the dimension values.
Moreover, for each cell of a chunk, the interleaving of the corresponding h-surrogates
yields a path-based key called the chunk-id, which is a unique identifier of a
data point in the multilevel multidimensional data space of a cube. For example,
0|0.0|0 is the chunk-id of the low-left cell of the chunk at depth D = 1 in Figure
6(b) (in the figure, it is depicted as a label on the corresponding chunk). ???P??? in a
chunk-id denotes a pseudo-level.
In Figure 8(a), we depict the abstract processing plan of Figure 5(b) as a physical
execution plan over a CUBE File organized fact table. We can see the evaluation of
the local predicate on the DATE dimension consisting of an HPP restriction solely
Figure 8. (a) The abstract processing plan of our running example expressed as a
physical execution plan over a CUBE File organized fact table; (b) the optimized
abstract plan
0 Karayannidis, Tsois, & Sellis
Copyright ?© 2007, Idea Group Inc. Copying or distributing in print or electronic forms without written permission of
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on the HPP-Index (a B-tree index defined on the hierarchy attributes of a dimension)
without the need to access the base table (i.e., the DATE dimension table). The
restriction Year = 1999 has been translated to the h-surrogate specification 0.
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