The landscape of information systems applications is comprised of legacy components that many times rely on heterogeneous data sources, proprietary data formats, and a low-level knowledge representation. Only seasoned programmers who maintain those systems may interpret these data. Ontology-based Data Access is a novel approach for developing information systems where an ontology defines a high-level global schema of already existing data sources and provides a vocabulary for user queries. In this work, we report on the construction of a system that exports such data, represented as a legacy relational database, as an OWL ontology in accordance to the W3C Direct Mapping specification. We discuss several case studies that show how the proposed application works.X Workshop Innovación en Sistemas de Software (WISS)Red de Universidades con Carreras en Informática (RedUNCI)