This paper focuses on the problems related to multi-model querying. We introduce MM-quecat, a tool that enables one to query multi-model data regardless of the underlying multi-model database or polystore.
Using category theory, we provide a unified abstract representation of multi-model data, which can be viewed as a graph and, thus, queried using a SPARQL-based query language. Moreover, the support for cross-model redundancy enables the choice of the optimal multi-model query strategy.