Panorama: A database system that annotates its answers to queries with their properties

摘要

When responding to queries, humans often volunteer additional information about their answers. Among other things, they may qualify the answer as to its reliability, and they may characterize it abstractly. This paper describes a relational database system that similarly annotates its answers with their properties. The process assumes that various assertions about properties of the data have been stored in the database (meta-information). These assertions are then used to infer properties of each answer provided by the system (meta-answers). Meta-answers are offered to users along with each answer issued, and help them to assess the value and meaning of the information that they receive. The advantages of the method described include: (1) It is extensible in that it allows users to determine the kinds of properties that the system will maintain and manipulate. (2) It has a built-in mechanism for determining the relevance of computed meta-information. (3) It is efficient: the number of operations required for meta-processing a given query can be expressed as a polynomial in the size of the meta-database. (4) It can be implemented externally with any commercial relational database system.