Abstract
Ontology-Based Data Access (OBDA) has emerged as a well-established approach to information management, facilitating access to a sole relational relational database via a high-level ontology and declarative mappings. In response to the challenges posed by Big Data, we propose the Ontology-Based Data Federation (OBDF) framework, which merges OBDA with Data Federation. This merging allows for the integration of numerous, distributed, and heterogeneous data sources in a virtual, uniform, and semantically coherent fashion.