Selective refutation of integrity constraints in deductive databases -- Approaches to updates over weak instances -- Index selection in relational databases -- Towards a schema design methodology for deductive databases -- Shared abstract data types: An algebraic methodology for their specification -- Specifying closed world assumptions for logic databases -- Interaction of authorities and acquaintances in the DORIS privacy model of data -- Logical rewritings for improving the evaluation of quantified queries -- Mathematical foundations of semantic networks theory -- Functional dependencies and the semilattice of closed classes -- An extended view on data base conceptual design -- Modeling planning problems -- On the interaction between transitive closure and functional dependencies -- A strategy for executing complex queries -- Multiple task selection protocol in a distributed problem solving network -- Equivalent schemes in semantic, nested relational, and relational database models -- Covers for functional independencies -- Restructuring and dependencies in databases -- RTL a Relation and Table Language for statistical databases -- Integration of functions in the fixpoint semantics of rule-based systems -- Locking policies and predeclared transactions -- Means for management of relational fuzzy data bases — Way to merging of systems of data bases and knowledge bases -- A specification language for static, dynamic and deontic integrity constraints -- Blocks and projections' synthesis in relational databases -- The higher-order entity-relationship model and (DB) -- Goal-oriented concurrency control -- Transitive closure and the LOGA+-strategy for its efficient evaluation.

This volume is a collection of the most important contributions presented at the second MFDBS conference held in Visegrád, Hungary, June 26-30, 1989. The papers selected from more than one hundred submissions, originating from 23 countries in 4 continents, can be roughly divided into the following sections: theoretical fundamentals of relational databases, logical foundations and databases, data modelling, database design, deductive databases, transaction management and security, concurrency control and distributed databases. The volume reflects the current state of knowledge and is a guide to further development in database theory.