An implementation model for reasoning with complex objects
Qiming Chen, Georges Gardarin · ACM SIGMOD Record · 1988
In this paper, we first propose a natural syntactical extension of DATALOG called NESTED_DATALOG for dealing with complex objects represented as nested predicates. Then, we introduce the token object model which is a simple extension of the relational model with tokens to represent complex objects and support referential information sharing. An implementation model of a NESTED_DATALOG program is defined by mapping it to the token object model which remains a straightforward extension of classical logical databases. Through this work, we can accommodate two basic requirements. The availability of a rule language for reasoning with complex objects, and the mechanism for mapping a complex object rule program to a relational DBMS offering a pure DATALOG rule language. In summary, the main contributions of the paper are the definition of a rule language for complex objects and the development of a technique to compile this complex object rule language to classical DATALOG.