Recent combinatorial results in the theory of relational databases

Recent results of the authors—some of which are joint with Thalheim and Seleznjev— in the area of combinatorial investigations of the relational database model are presented here. In relational databases keys—combinations of attributes uniquely identifying the records—play an important role. The structure and size of keys have been widely investigated. Here, after a short review of the earlier results, we discuss two generalizations: the (average) structure and size of keys in a random database and the concept of error-correcting keys in case of unreliable data collection.