C. Hurtado, A.O. Mendelzon, and A. Vaisman. Updating OLAP dimensions. Proceedings of ACM DOLAP'99, 1999. Home/Search Document Details and Download
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Evolution of Dimension Data in Temporal Data Warehouses - Eder, Koncilia (Correct)
....show how changes of the conceptual schema can be automatically transfered into the logical and internal schema. However, these papers do not deal with the inevitable consequences arising out of these scheme evolutions like misinterpretations of analyzes. C. Hurtado, A. Mendelzon and A. Vaisman [9] have proposed a formal description of complex operators to delete, insert and or update dimensions at a structural and at an instance level. However, they do not cope with the problem regarding the availability of data and they do not deal with the fact that several versions of dimensions may ....
C. Hurtado, A. Mendelzon, and A. Vaisman. Updating OLAP Dimensions. In Proc. of the ACM Second Int. Workshop on Data warehousing and OLAP, USA, 1999.
Supporting Dimension Updates in an OLAP - Server Alejandro Vaisman Self-citation (Mendelzon Vaisman) (Correct)
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C. Hurtado, A.O. Mendelzon, and A. Vaisman. Updating OLAP dimensions. Proceedings of ACM DOLAP'99, 1999.
Supporting Dimension Updates in an OLAP Server - Vaisman, Mendelzon, Ruaro.. (2002) Self-citation (Mendelzon Vaisman) (Correct)
....Section 2 we review the multidimensional model and dimension updates; in Section 3 we describe our implementation in detail. Section 4 presents the case study and discusses the results. We conclude in Section 5. 2 Multidimensional Model and Dimension Updates In previous work, Hurtado et al. [6,7] introduced a multidimensional model that includes a framework for dimension updates and a set of dimension update operators. Due to space limitations we will only give a quick overview of that model, and refer the reader to these works fordetails. A dimension schema is a directed acyclic graph ....
....Mendoza City, to the instance of Figure 2(a) Many common updates to dimensions would result in long sequences of primitive instance updates. Thus, the works cited above define complex instance update operators, capturing such common sequences and encapsulating them in a single operation [6,7]. When an update to a dimension occurs, any cube views that have been materialized in the data warehouse must be updated accordingly. revious works [6,13] present algorithms that outperform traditional incremental maintenance algorithms for materialized views with aggregates [11] by exploiting ....
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C. Hurtado, A. O. Mendelzon, and A. Vaisman. Updating OLAP dimensions. Proceedings of ACM DOLAP'99, 1999. 68, 69, 70
Reasoning about Summarizability in Heterogeneous.. - Hurtado, Mendelzon (2001) (2 citations) Self-citation (Hurtado Mendelzon) (Correct)
....consists of a set of members for each level, called member sets; and a hierarchy relation that models the ancestor descendant relation between the members. For instance, we may have T oronto as a member of a level City in a dimension representing locations. In most of the models [CT97] HMV99a] HMV99b] the hierarchy relation is represented by a set of functions between member sets, called rollup functions. Usually, we say that a level l 1 rolls up to another level l 2 when there exists an edge from l 1 to l 2 in the hierarchy, meaning that there is a rollup function from l 1 to l 2 . 1.1 ....
....flexible model at the logical layer can also be propagated to the storage layer. For instance, heterogeneity allows the fusion of levels that share attributes, while keeping separate levels with different attributes. We end this section by noting that current dimension models [CT97] HMV99a] HMV99b] JLS99] do not allow heterogeneity. USA Canada all s2 s1 New York Nystate Toronto Ontario Country All Store Country All City State Province State Province Store City PoliticalDiv. Country All (D) CityUSA CityCanada StoreUSA StoreCanada (B) A) C) Fig. 1. A) B) C) Three ....
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C. Hurtado, A. Mendelzon, and A. Vaisman. Updating OLAP dimensions. In Proceedings of the 2nd IEEE-DOLAP Workshop, Kansas City, Missouri, USA, 1999.
Updating OLAP Dimensions - Hurtado, Mendelzon, Vaisman (1 citation) Self-citation (Hurtado Mendelzon Vaisman) (Correct)
....SQL. We study two possible implementations: a) dimensions are stored as a single table (denormalized case) and (b) dimensions are stored as a set of normalized tables. We present the details of the implementation of the Reclassify operators. We refer the reader to the full version of this paper [4] for details on the remaining operators. 3.1 Mapping Dimensions to Relations Denormalized Representation The idea in the denormalized representation is to build a single table containing all the rollups in the dimension. Schema The schema Sd = rname; A;F) of the relation is defined as follows: ....
C. Hurtado, A. Mendelzon, and A. Vaisman. Updating OLAP dimensions (extended version). URL: ftp://ftp.db.toronto.edu/pub/ papers /fulldolap99.ps.gz.
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