Specifying Aggregation Functions in Multidimensional Models with OCL

Abstract

Abstract. Multidimensional models are at the core of data warehouse systems, since they allow decision makers to early define the relevant information and queries that are required to satisfy their information needs. The use of aggregation functions is a cornerstone in the definition of these multidimensional queries. However, current proposals for multidimensional modeling lack the mechanisms to define aggregation functions at the conceptual level: multidimensional queries can only be defined once the rest of the system has already been implemented, which requires much effort and expertise. In this sense, the goal of this paper is to extend the Object Constraint Language (OCL) with a predefined set of aggregation functions. Our extension facilitates the definition of platform-independent queries as part of the specification of the conceptual multidimensional model of the data warehouse. These queries are automatically implemented with the rest of the data warehouse during the code-generation phase. The OCL extensions proposed in this paper have been validated by using the USE tool.

EMF Views: A View Mechanism for Integrating Heterogeneous Models

“…As further work, we plan to enrich our view mechanism with support for a limited set of aggregation operations, focusing on distributive aggregate functions [21] expressed with OCL extensions [8]. This will be linked to addressing the view update challenge [20], as EMF Views is currently limited to individual attribute updates.…”

“…Its base platform was SmartEA 5 that integrates TOGAF 6 . Use case providers wanted to customize SmartEA and also include both business process information defined using BPMN 7 and requirement specifications defined with ReqIf 8 . Besides integrating BPMN and ReqIf models as part of SmartEA, they wanted to be able to interconnect these models with the TOGAF ones and to provide partial views on the combined models depending on given profiles (e.g., with restricted access for security reasons).…”

Aggregating and Disaggregating Flexibility Objects

“…Complex objects with multidimensional data exist in many real-world applications [17] and can be represented with multidimensional data models [18]. Several research efforts (e.g., [19] and [20]) have been proposed to aggregate complex objects. However, these efforts do not consider the specific challenges related to aggregating flex-objects.…”

Object Constraint Language (OCL): A Definitive Guide

“…On the other hand, the library is missing some relevant operators, like basic statistical functions [9] that make cumbersome using OCL in some domains.…”