Due to the increasing availability of data sources, concerning also complex and highly structured domains, an ever greater number of unskilled users face the need of accessing databases by formulating sophisticated queries. In such cases it is difficult to provide the user with the knowledge she/he needs to fully understand the semantics of the searched data, and with tools powerful enough to allow her/him to formulate the intended queries. The so called Visual Query Systems (VQS) try to overcome these difficulties by providing the user with several graphic oriented paradigms for visualizing the conceptual models of the application domains, and by allowing her to build queries by means of visual oriented interactions. In the present paper we propose a paradigm for supporting the user in building sophisticated queries to object oriented databases. The paradigm is based on a uniform graphical presentation of the domain model and the queries. Most notably, it is also based on a representation of the conceptual model of the database via Description Logics. In this way it is possible to perform some relevant inferential tasks on the query, in order to allow the user to: - interactively and iteratively build queries; - be prevented from building inconsistent queries; - interactively explore the semantics of the domain model; - be gradually introduced only to those part of the domain model relevant to the query formulation; - be provided with simple, but effective, features for query refinement and query generalization. The paradigm we propose has been implemented in a first prototype system, briefly presented in the present paper.
A Knowledge Based Paradigm for Querying Databases
Bresciani, Paolo;Nori, Michele;
2000-01-01
Abstract
Due to the increasing availability of data sources, concerning also complex and highly structured domains, an ever greater number of unskilled users face the need of accessing databases by formulating sophisticated queries. In such cases it is difficult to provide the user with the knowledge she/he needs to fully understand the semantics of the searched data, and with tools powerful enough to allow her/him to formulate the intended queries. The so called Visual Query Systems (VQS) try to overcome these difficulties by providing the user with several graphic oriented paradigms for visualizing the conceptual models of the application domains, and by allowing her to build queries by means of visual oriented interactions. In the present paper we propose a paradigm for supporting the user in building sophisticated queries to object oriented databases. The paradigm is based on a uniform graphical presentation of the domain model and the queries. Most notably, it is also based on a representation of the conceptual model of the database via Description Logics. In this way it is possible to perform some relevant inferential tasks on the query, in order to allow the user to: - interactively and iteratively build queries; - be prevented from building inconsistent queries; - interactively explore the semantics of the domain model; - be gradually introduced only to those part of the domain model relevant to the query formulation; - be provided with simple, but effective, features for query refinement and query generalization. The paradigm we propose has been implemented in a first prototype system, briefly presented in the present paper.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
