LOGIDATA+ is part of the subproject Advanced Database Systems of the project Information Systems and Parallel Computation, of the Italian research council. The aim of LOGIDATA+ is the definition of advanced database systems, which significatively extend the functionalities of the current systems, with specific reference to the application areas for which relational systems are not considered satisfactory. These new systems will allow the definition of data with complex structures, the representation of semantic relationships between objects, and the use of powerful query and update languages. They will be based on the combination of techniques originating from relational databases and logic programming, with contributions from object-oriented programming. Attention will be devoted to the representation of isa-hierarchies and to taxonomic reasoning.