The following are the four declarative mechanisms, used for representing knowledge:
(a) Semantic Nets: - These describe both objects and events in general
(b) Conceptual Dependency:- Provides a way of representing relationships among components of an action.
© Frames:- A general structure to represent complex objects from several different points of view.
(d) Scripts: A sophisticated structure use to represent common sequence of events.
All these structures share a common notion that complex entities can be describe as a collection of attributes and associated values (hence they are often called “slot-and –filter structures”) ie., these structures have the form of ordered triples
OBJECTS x ATTRIBUTES x VALUE
Information can be retrieved from the knowledge base by an associative search with VALUE.