tailieunhanh - Panorama: A Database System that Annotates Its Answers to Queries with their Properties

Services must be configured with the Server Control (SRVCTL) utility identically on all databases in a Data Guard configuration. In the following examples, a service named oltpworkload is configured to be active when the database Austin is in the primary role (-l PRIMARY). The same service is also configured on the standby database Houston so that is started whenever Houston functions in the primary role. Similarly, a second service named reports is configured to be started when Austin or Houston are functioning in the standby database role (-l PHYSICAL_STANDBY). The reports service provides real-time reporting using Active Data. | Journal of Intelligent Information Systems 7 51-73 1996 1996 Kluwer Academic Publishers Boston. Manufactured in The Netherlands. Panorama A Database System that Annotates Its Answers to Queries with their Properties AMIHAI MOTRO ami@ Department of Information and Software Systems Engineering George Mason University Fairfax VA 22030-4444 Abstract. 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 . Metaanswers 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. Keywords relational database cooperative answering answer characterization meta-answer 1. Introduction Given a query a typical database system is concerned only with answering it correctly and efficiently. In contrast when responding to similar 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. As a simple example .