The IsaLog ¬ model and language are presented. The model has complex objects with classes, relations, and isa hierarchies. The language is strongly typed and declarative. The main issue is the definition of the semantics of the IsaLog language. The novel features are mostly due to the interaction of hierarchies with negation in the body of rules. Two semantics are presented and shown to be equivalent: a stratified semantics based on an original notion of stratification, needed in order to correctly deal with hierarchies, and a reduction to logic programming with function symbols. The solutions are based on a new technique (explicit Skolem functors) that provides a powerful tool for manipulating object identifiers.
IsaLog¬: A Deductive Language with Negation for Complex-Object Databases with Hierarchies
MECCA, Giansalvatore
1993-01-01
Abstract
The IsaLog ¬ model and language are presented. The model has complex objects with classes, relations, and isa hierarchies. The language is strongly typed and declarative. The main issue is the definition of the semantics of the IsaLog language. The novel features are mostly due to the interaction of hierarchies with negation in the body of rules. Two semantics are presented and shown to be equivalent: a stratified semantics based on an original notion of stratification, needed in order to correctly deal with hierarchies, and a reduction to logic programming with function symbols. The solutions are based on a new technique (explicit Skolem functors) that provides a powerful tool for manipulating object identifiers.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
