Marcelo De Vincenzi

Design method for a Historical Data Warehouse, explicit valid time in multidimensional models

We present a new storage structure that contains the explicit valid time called Historical DW. This proposal combines a Historical Data Base and a DW in one integrated model. The objective of this model is to solve the temporal limitations of the traditional multidimensional structures. Although the Temporal DW considers, besides the temporal dimension, other aspects related to time, this model only takes into account the changes that occur in the DW schema, both in dimensions and in hierarchies. Therefore, considering the need for registering values that allow to evaluate trends, variations, maximum and minimum values, a problem to be solved is how to shape the values of entities, attributes or relationships that may vary in time, in the design of the structure. The fact that the needed data was stored is already known, but the temporal search mechanisms would be complex. The Historical DW design is framed in the MDD approach, a strategy that allows, through successive automatic transformations, to obtain one of the implementations of the model in a Relational Data Base Management System (RDBMS).

Graphical Query Mechanism for Historical Data Warehouse within MDD

Query tools that depend on the ability of programmers, impose a cognitive load that could reduce the users productivity. Within MDD, the proposal of our work is the creation of a visual query mechanism derived from a historical multidimensional data structure. This mechanism facilitates (and partially automates) the formulation of temporal and decision making queries.