An Application of Problem Solving Techniques

the relational data base model the L2 mad& presented here. ABSTRACT The principal restrictions previously placed on have been removed in We extend the model to include rz& (i.e. unknown and non-relevant) values (even in keys), repetitions of tuples, functional dependencies, a very rich set of constraints and information originating from several sources. The programmed problem-solver ALICE is utilized to manipulate the constraints and to simplify relations: to answer a query, ALICE selects both the tuples which m@ti answer the query upon appropriate substitutions for u&noLVn values.