Functional Dependencies for XML

Vincent, Millist W.; Liu, Jixue

doi:10.1007/3-540-36901-5_3

Cited by 38 publications

(32 citation statements)

References 8 publications

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“…With a recent shift to XML as a data model, many of classical database subjects have been reexamined in the XML context, among them design and normalization [4,35,37,36,20,38]. The goal of normalization is to eliminate redundancies from a database or an XML document, and by doing so, eliminate or reduce potential update anomalies.…”

Section: Introductionmentioning

confidence: 99%

XML design for relational storage

Kolahi

Libkin

2007

Proceedings of the 16th International Conference on World Wide Web

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Design principles for XML schemas that eliminate redundancies and avoid update anomalies have been studied recently. Several normal forms, generalizing those for relational databases, have been proposed. All of them, however, are based on the assumption of a native XML storage, while in practice most of XML data is stored in relational databases.In this paper we study XML design and normalization for relational storage of XML documents. To be able to relate and compare XML and relational designs, we use an information-theoretic framework that measures information content in relations and documents, with higher values corresponding to lower levels of redundancy. We show that most common relational storage schemes preserve the notion of being well-designed (i.e., anomalies-and redundancyfree). Thus, existing XML normal forms guarantee welldesigned relational storages as well. We further show that if this perfect option is not achievable, then a slight restriction on XML constraints guarantees a "second-best" relational design, according to possible values of the informationtheoretic measure. We finally consider an edge-based relational representation of XML documents, and show that while it has similar information-theoretic properties with other relational representations, it can behave significantly worse in terms of enforcing integrity constraints.

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Section: Introductionmentioning

confidence: 99%

XML design for relational storage

Kolahi

Libkin

2007

Proceedings of the 16th International Conference on World Wide Web

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“…In particular, they showed that for a very general class of mappings from relations to XML, a relation satisfies a functional dependency if and only if the corresponding XML document satisfies the corresponding XML functional dependency. Thus there is a natural correspondence between functional dependencies in relations and functional dependencies in XML as defined in [9,10,11]. The other contributions of [9,10,11] were to show that the definition of a FD in XML is a generalization of keys as defined in [6] and to propose a normal form for XML and prove that it is a necessary and sufficient condition for the elimination of redundancy.…”

Section: Introductionmentioning

confidence: 97%

“…Recently [9,10,11], the authors have shown how to define functional dependencies in XML in a way that naturally generalizes the definition of functional dependencies in relations. In particular, they showed that for a very general class of mappings from relations to XML, a relation satisfies a functional dependency if and only if the corresponding XML document satisfies the corresponding XML functional dependency.…”

Section: Introductionmentioning

confidence: 97%

Local XML functional dependencies

Liu

Vincent

Liu

2003

Proceedings of the 5th ACM International Workshop on Web Information and Data Management

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Keys and functional dependencies play a fundamental role in relational databases where they are used in integrity enforcement and in database design. Similarly, these constraints will play a fundamental role in XML and recently keys and functional dependencies in XML have been defined. In this paper we extend the previous definition of functional dependencies in XML to local functional dependencies in XML. Local functional dependencies (LFDs) are functional dependencies which hold only in a certain part of an XML document and not in the whole document. We also define, and prove correct, axioms for reasoning about the implication of LFDs in XML. Finally, we examine the relationship between LFDs and keys and show that the recently introduced concept of a relative key is a special case of a LFD.

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“…Liu etc. defined XFD, XMVD [9,[12][13][14] and relative normal form based XML intermediate attributes FD and MVD. And some literatures researched XML Key [2,3], XML functional dependency [4-6, 10, 11, 15] and XML normalization [1,7,16].…”

Section: Introductionmentioning

confidence: 99%

XML Functional Dependency and Schema Normalization

Zhao

Xin

Zhang

2009

2009 Ninth International Conference on Hybrid Intelligent Systems

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Normalization theory is necessary for designing a good XML document. A good document means that it has minimal redundancy. The research on XML functional dependency and normalization is still an open problem. This paper first presents a path language of XML model, then proposes a new kind of XML functional dependency (XFD) that has stronger expression ability to XML functional dependency that can result in redundancies. In this paper, the problems of XFD logical implication and XFD closure are studied and a group of the corresponding inference rules is proposed. Based on the XFD, a kind of XML normal form (XNF) and an algorithm converting into XNF are also proposed in this paper.

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Functional Dependencies for XML

Cited by 38 publications

References 8 publications

XML design for relational storage

XML design for relational storage

Local XML functional dependencies

XML Functional Dependency and Schema Normalization

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