Objects in relational database schemes with functional, inclusion, and exclusion dependencies
نویسندگان
چکیده
منابع مشابه
Null Inclusion Dependencies in Relational Databases
Functional dependencies (FDs) and inclusion dependencies (INDs) are the most fundamental integrity constraints that arise in practice in relational databases. We introduce null inclusion dependencies (NINDs) to cater for the situation when a database is incomplete and contains null values. We show that the implication problem for NINDs is the same as that for INDs. We then present a sound and c...
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In this article we define a new type of integrity constraint in XML, called an XML inclusion constraint (XIND), and show that it extends the semantics of a relational inclusion dependency. This property is important in areas such as XML publishing and ‘data-centric’ XML, and is one that is not possessed by other proposals for XML inclusion constraints. We also investigate the implication and co...
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متن کاملLogical Database Design with Inclusion Dependencies
Contrary to popular belief, relation schemes in good classical normal forms are not necessarily devoid of redundancies. This arises from the fact that classical data dependencies are oblivious to important constraints which may exist between sets of attributes occuring in different relation schemes. In this paper, we study how inclusion dependencies (INDs) can be used to model these constraints...
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A two-step optimization strategy for relational schemas that contains a class of inclusion dependencies is described. Both steps take into account additional information that indicates how to preserve each inclusion dependency in the presence of insertions an‘d deletioy. The first step eliminates inclusion dependencies which are redundant with respect to both the semantics of the data and the b...
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ژورنال
عنوان ژورنال: RAIRO - Theoretical Informatics and Applications
سال: 1993
ISSN: 0988-3754,1290-385X
DOI: 10.1051/ita/1993270301831