Wydział Fizyki Technicznej, Informatyki i Matematyki Stosowanej / Faculty of Technical Physics, Information Technology and Applied Mathematics / W7
Stały URI zbioruhttp://hdl.handle.net/11652/7
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Pozycja Integrity Rules for Multiargument Relationships in Possibilistic Databases(Wydawnictwo Politechniki Łódzkiej, 2016) Myszkorowski, KrzysztofThe paper contains an analysis of multiargument relationships in possibilistic databases. A multiargument relationship may be formally presented using the relational notation R(X1, X2,...,Xn), where R is the name of the relationship and attributes Xi denote keys of entity sets which participate in it. The dependencies between all n attributes describe the integrity constraints and must not be infringed. They constitute a restriction for relationships of fewer attributes. In the paper it is considered a possible coexistence of associations between k < n attributes of the n-ary relationship. The analysis is carried out using the theory of fuzzy functional dependencies. The notion of functional dependency has been appropriately extended according to the representation of data.Pozycja Klasyczne i rozmyte bazy danych : modele, zapytania i podsumowania(Akademicka Oficyna Wydawnicza EXIT, Warszawa, 2008) Zadrożny, Sławomir; Myszkorowski, Krzysztof; Szczepaniak, Piotr S.; Piecha, JanPozycja Fuzzy querying with the use of interval-valued fuzzy sets(Wydawnictwo Politechniki Łódzkiej, 2013) Myszkorowski, Krzysztof; Superson, IzabelaThe paper deals with flexible queries in relational databases. Conditions included in queries are modeled with the use of interval-valued fuzzy sets. Each value returned by a query is associated with a subinterval of [0,1] which expresses a membership degree. The bounds of membership intervals have been determined for different operations of relational algebra and different SQL operators.