A Galois connection is stated between a knowledge base and queries over this knowledge. Queries are stated as conjunctions. Both the knowledge and queries are represented by certain graphs. This Galois connection gives rise to lattices of pattern concepts implicitly contained in the theory (all derivable facts) over the knowledge base. The formal foundation for browsing such lattices and a realisation in terms of a prototype tool is outlined. Data types may be assigned to individual columns of tables in the database