The Semantic Web comprises various standards for knowledge representation. Topic Maps and RDF are the most popular among them. Both provide a data model that seems at first glance indistinguishable from one another but each one having its own features makes it difficult to extract data from both models simultaneously. The purpose of this paper is to provide a query model applicable to both RDF and Topic Maps data models. To achieve this, it proposes the definition of a lightweight ontology and queries using Datalog. Mappings will then allow data querying regardless of the models used by data sources