This monograph describes a method of data modelling whosebasic aim is to make databases easier to use by providingthem with logical data independence. To achieve this, thenested UR (universal relation) model is defined by extendingthe classical UR model to nested relations. Nested relationsgeneralize flat relations and allow hierarchicallystructured objects to be modelled directly, whereas theclassical UR model allows the user to view the database asif it were composed of a single flat relation. The authorpresents a comprehensive formalisation of the nestedrelational model, which incorporated null values into themodel. Functional data dependencies and the classical notionof lossless decomposition are extended to nested relationsand an extended chase procedure is defined to test thesatisfaction of the data dependencies. The nested UR modelis defined, and the classical UR model is shown to be aspecial case of the nested model.This implies that an URinterface canbe implemented by using the nested UR model,thus gaining the full advantages of nested relations overflat relations.
Le informazioni nella sezione "Riassunto" possono far riferimento a edizioni diverse di questo titolo.
The underlying database models.- The null extended nested relational model.- Null extended data dependencies and the extended chase.- A universal relation model for a nested database.- A universal relation model for a single nested relation.- Concluding remarks and ongoing research.
Le informazioni nella sezione "Su questo libro" possono far riferimento a edizioni diverse di questo titolo.
Da: Ammareal, Morangis, Francia
Softcover. Condizione: Bon. Ancien livre de bibliothèque. Légères traces d'usure sur la couverture. Edition 1992. Ammareal reverse jusqu'à 15% du prix net de cet article à des organisations caritatives. ENGLISH DESCRIPTION Book Condition: Used, Good. Former library book. Slight signs of wear on the cover. Edition 1992. Ammareal gives back up to 15% of this item's net price to charity organizations. Codice articolo E-582-848
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Da: Ria Christie Collections, Uxbridge, Regno Unito
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Da: Revaluation Books, Exeter, Regno Unito
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Da: moluna, Greven, Germania
Condizione: New. This monograph describes a method of data modelling whosebasic aim is to make databases easier to use by providingthem with logical data independence. To achieve this, thenested UR (universal relation) model is defined by extendingthe classica. Codice articolo 4893622
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Da: Buchpark, Trebbin, Germania
Condizione: Sehr gut. Zustand: Sehr gut | Sprache: Englisch | Produktart: Bücher | This monograph describes a method of data modelling whosebasic aim is to make databases easier to use by providingthem with logical data independence. To achieve this, thenested UR (universal relation) model is defined by extendingthe classical UR model to nested relations. Nested relationsgeneralize flat relations and allow hierarchicallystructured objects to be modelled directly, whereas theclassical UR model allows the user to view the database asif it were composed of a single flat relation. The authorpresents a comprehensive formalisation of the nestedrelational model, which incorporated null values into themodel. Functional data dependencies and the classical notionof lossless decomposition are extended to nested relationsand an extended chase procedure is defined to test thesatisfaction of the data dependencies. The nested UR modelis defined, and the classical UR model is shown to be aspecial case of the nested model.This implies that an URinterface canbe implemented by using the nested UR model,thus gaining the full advantages of nested relations overflat relations. Codice articolo 536907/202
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Da: Buchpark, Trebbin, Germania
Condizione: Sehr gut. Zustand: Sehr gut | Sprache: Englisch | Produktart: Bücher | This monograph describes a method of data modelling whosebasic aim is to make databases easier to use by providingthem with logical data independence. To achieve this, thenested UR (universal relation) model is defined by extendingthe classical UR model to nested relations. Nested relationsgeneralize flat relations and allow hierarchicallystructured objects to be modelled directly, whereas theclassical UR model allows the user to view the database asif it were composed of a single flat relation. The authorpresents a comprehensive formalisation of the nestedrelational model, which incorporated null values into themodel. Functional data dependencies and the classical notionof lossless decomposition are extended to nested relationsand an extended chase procedure is defined to test thesatisfaction of the data dependencies. The nested UR modelis defined, and the classical UR model is shown to be aspecial case of the nested model.This implies that an URinterface canbe implemented by using the nested UR model,thus gaining the full advantages of nested relations overflat relations. Codice articolo 536907/2
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