Knowledge representations for database metadata

摘要

We introduce the notion of metadata and the role it plays in a user's understanding of data in a database. We survey the kinds of metadata present in database schemas through an Abstract Conceptual Schema, and also the kinds of metadata associated with frames in knowledge engineering tools. Finally we look at networks used for natural language understanding, (KL-ONE and MEMORY), and describe a metadata knowledge representation (MAKR) which relates database metadata to a KL-ONE style meaning representation. Examples in MARK are used to illustrate the kinds of metadata surveyed in the first part of the paper.