Nowadays, the term sustainability gains more and more importance in corporate risk management and decision making. Corporate Sustainability Information Systems should support companies to analyse sustainability risks and provide relevant data in a practical manner. A major challenge in the domain of sustainability is to integrate environmental, social and economic data from different sources. This paper presents an approach for ontology-based data integration in the Corporate Sustainability domain preserving hierarchical relations to allow e.g. improved querying. Based on an existing sustainability framework defined in an XBRLtaxonomy, first a mechanism for the automatic generation of a domain-specific ontology is proposed. Finally, special data is queried and linked to the proposed ontology, serving as a working example for the suggested approach.