An Object-Oriented Pattern Matching Language

A graphical model for describing schemes and instances of object-databases and a graphical data manipulation language based on pattern matching, called PaMaL, are introduced. The operations of PaMaL (addition and deletion of nodes and edges) use patterns to indicate the parts of the instance that are affected by the operation. We give the syntax and semantics of the operations and the programming constructs (loop, procedure and program) of PaMaL. We add a reduce-operation to work with a special group of instances, the reduced instances. 1 Introduction One of the first visual or graphical interfaces for databases was QBE [Zlo77]. It introduced a new way of user-database interaction, by providing the user some tools to interact directly with the database and its structure. Since then, the research of visual interfaces has evolved in two directions. One group develops specialized interfaces for geographical or pictorial information (some relevant information can be found in [vl, Coo93])..