Abstract
In information retrieval systems storage occupancy is in general disregarded to take advantage in running time; in an environment in which retrieval time is not a primary requirement (this is the case of Data Base Machines), transposed files become a very interesting structure; in fact they allow a considerable space saving with respect to fast access structures, such as inverted files. But transposed files, in most cases, are not practicable, as theyare to be searched by a sequential scanning.
In this paper a structure is defined to implement transposed files, called 2-B tree, which is a sort of two-dimensionalB-tree, and avoid sequential scanning; search in a trasposed file stored as a 2-B tree in π memory pages is 0 (π1/2), while insertion and deletion are 0 (logπ). Moreover, 2-B tree organization can achieve an improvement in storage requirements up to 42% with respect to inverted file organization.
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Gambacorta, A., Leoni, G. Una struttura bidimensionale per la memorizzazione dei file trasposti. Calcolo 19, 397–414 (1982). https://doi.org/10.1007/BF02575768
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DOI: https://doi.org/10.1007/BF02575768