Bipolar SQLf: a Flexible Querying Language for Relational Databases

International audienceFlexible querying of information systems allows expressing complex preferences in user queries. Such preferences can be modeled by fuzzy bipolar conditions which are made of constraints c and wishes w and interpreted as "to satisfy c and if possible to satisfy w".We de ne in this article the main elements of the Bipolar SQLf language, which is an SQL-like querying language based on a bipolar relational algebra. This language is an extension of the SQLf language. Basic statements (projection, selection, etc.) are firstly defined in terms of syntax, evaluation and calibration. Then, complex statements, such as bipolar queries based on nesting operators are studied in terms of expression, evaluation, query equivalence and backward compatibility with the SQLf language

Fuzzy Bipolar Conditions of Type "or else"

International audiencePreviously studied fuzzy bipolar conditions of type "and if possible" are made of a mandatory condition c and an optional condition w. They allow expressing complex preferences of a conjunctive nature. We define in this paper, a new kind of fuzzy bipolar conditions of the form "or else" which express complex preferences of a disjunctive nature. We show that the "or else" form can be used as a negation operator of the "and if possible" form and vice versa. We also show that these both forms are compatible and, therefore, fuzzy bipolar conditions of both types can be used together in the same bipolar query

An Extension of a Fuzzy Ontology for Flexible Querying

International audienceIn this paper, we propose a personalized approach for flexible querying of information systems. This approach consists in the combination of the reasoning capabilities of the fuzzy DLR-Lite ontology and the expressivity of the SQLf language. The interpretation of the gradual inclusion (subsumption) axioms of the ontology is based on the G¨odel fuzzy implication. Its generalization to a tree of inclusions is also proposed. This tree and its property of propagation of degrees are the basic theoretical elements of our application, which consists in querying of a multimodal transport information system which is embedded in a mobile terminal characterized by limited storage and processing capabilities

Bipolarity and the relational division

International audienceA fuzzy bipolar relation is a relation defined by a fuzzy bipolar condition, which could be interpreted as an association of a constraint and a wish. In this context, the extension of the relational division operation to bipolarity is studied in this paper. Firstly, we define a bipolar division when the involved relations are crisp. Then, we define, from the semantic point of view, several forms of bipolar division when the involved relations are defined by fuzzy bipolar conditions. These forms of division can be related to the general model of fuzzy bipolar division introduced by Bosc and Pivert

Les Conditions Multipolaires Floues

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A Relational Division Based on a Fuzzy Bipolar R-Implication Operator

International audienceWe introduce in this paper a new relational division operator based on a bipolar implication operator involving fuzzy bipolar relations. The considered bipolarity encompasses two kinds of bipolar conditions: the former is of type "and if possible", and the latter is of type "or else". This new division operator allows as to express a division of bipolar relations regardless of the nature of the dividend and the divisor (Boolean, fuzzy, bipolar, homogeneous, heterogeneous). We have also shown that the proposed relational division operator satisfies the bipolar quotient properties and can be an alternative to the already proposed operator in [1]-[3] which is based on the quantities involved in the division operation. The new proposed operator is aimed to be integrated into the bipolar SQLf language for flexible querying of relational databases

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Bipolarity in Flexible Querying of Information Systems Dedicated to Multimodal Transport Networks

International audienceFlexible querying of information systems dedicated to multimodal transport networks aims to help user organizing his/her trips by promoting public transport networks (bus, subway, train, boat, plane, etc.). In this context, it is necessary to provide an integrated environment in which it is possible for the user to express queries with complex preferences so as to meet his/her expectations. Complex preferences are modeled by fuzzy bipolar conditions which associate negative and positive conditions. Queries involving such conditions are called bipolar queries. In our case, such queries are addressed to multimodal transport information systems, which are often made of several distributed and heterogeneous databases. Therefore, semantic aspects have to be taken into consideration in the querying process so that only the most relevant data is targeted to evaluate queries. We introduce then in this paper a new approach for flexible querying of information systems that combines a reasoning mechanism (fuzzy bipolar DLR-Lite) with a relational language of a high expressiveness (bipolar SQLf language)

Ontology-Based Evaluation of Fuzzy Bipolar Conjunctive Queries over Relational Databases

In the wake of flexible querying system, proposed in [26], [28], [29], in which the bipolarity of the form "and if possible" is used as means to express user preferences over relational databases and ontologies (fuzzy bipolar DLR-Lite), we introduce in this paper the user query evaluation process, under the extension of our flexible querying framework to bipolar conditions of the form "or else" [20], [19]. Queries addressed to our system are bipolar conjunctive queries made of a conjunction of atoms corresponding to concepts of an ontology. The proposed evaluation process is carried out in two main steps. The former consists of query derivation to compute complementary queries, based on substitutions of query's atoms involved in fuzzy bipolar subsumptions expressed in the considered bipolar ontology. The latter deals with the translation of the obtained set of queries from the first step into bipolar SQLf statements, which are finally evaluated over a bipolar relational database managed by PostgreSQLf DBMS extended to bipolar datatypes and functions. Three algorithms are then developed in order to perform applicable substitutions, to derive corresponding complementary queries and to translate them into Bipolar SQLf statements. The feasibility of the approach is shown through a prototype developed in the field of multimodal transport systems