Towards Quality-Oriented Data Warehouse Usage and Evolution

As a decision support information system, a data warehouse must provide high level quality of data and quality of service. In the DWQ project we have proposed an architectural framework and a repository of metadata which describes all the data warehouse components in a set of metamodels to which is added a quality metamodel, defining for each data warehouse metaobject the corresponding relevant quality dimensions and quality factors. Apart from this static definition of quality, we also provide an operational complement, that is a methodology on how to use quality factors and to achieve user quality goals. This methodology is an extension of the Goal-Question-Metric (GQM) approach, which allows to capture (a) the inter-relationships between different quality factors and (b) to organize them in order to fulfil specific quality goals. After summarizing the DWQ quality model, this paper describes the methodology we propose to use this quality model, as well as its impact on the data warehouse evolution.