'R a1' diaporamas de présentation

Functional Dependencies and Normalization for Relational Databases

CHAPTER 10. Functional Dependencies and Normalization for Relational Databases. Informal Design Guidelines for Relational Databases. Semantics of the Relation Attributes Reducing the redundant values in tuples Reducing the null values in tuples

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Database Systems Chapter 6 The Relational Algebra

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Relational Algebra

Relational Algebra. The basic set of operations for the relational model is the relational algebra. enable the specification of basic retrievals The result of a retrieval is a new relation, which may have been formed from one or more relations.

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Relational Data Model

Relational Data Model. A Brief History of Data Models. 1950s file systems, punched cards 1960s hierarchical IMS 1970s network CODASYL, IDMS 1980s relational INGRES, ORACLE, DB2, Sybase Paradox, dBase 1990s object oriented and object relational O2, GemStone, Ontos.

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Original situation

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