Towards a Co-operative Data Base Management System

A desirable feature of any high-level data base query system is that it should be userfriendly. This should ex tend beyond the provision of a query syntax which is easy to use, to some attempt at intelligent helpfulness or cooperativeness. In particular additional knowledge about the structure of the data in a data base or the incomplete data contained in a query may be used to benefit the user. In this respect, despite its simplicity and ease of use, the data base management language Query-by-Example is relatively inflexible. This paper looks at several ways in which the co-operativeness of Qu~ry-by-Example can be improved. These are concerned with incomplete queries (i.e. queries in which certain information has been omitted), incomplete updates and queries which fail as a result possibly of misconceptions on the part of the user. Consideration is also given to how these are implemented in Prolog. JC Neves and M H Williams