A new normal form for nested relations

Özsoyoğlu, Z. Meral; Yuan, Li-Yan

doi:10.1145/12047.13676

Cited by 126 publications

(91 citation statements)

References 17 publications

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“…According to conditions 2 and 3 in Definition 3.6, NF-NR satisfies this property. Both NF in [11] and NNF in [12] satisfy this property(in the case of flat relations, they all reduce to 4NF). However, since NNF does not distinguish between FD and MVD, which usually appear in flat relations, it reduces to 4NF but does not allow the existence of any non-trivial FD.…”

Section: Property 1: Normal Form For Nested Relations Should Reduce Tmentioning

confidence: 98%

“…By this we ensure that the undesirable anomalies are eliminated. Both NF [11] and NNF [12] satisfy this property. However, the result of decomposition might be quite different from one another.…”

Section: Property 2: a Normalized Nested Relation Can Be Represented mentioning

confidence: 99%

“…Several normal forms for nested relations were proposed [11,12,9]. These normal forms are proposed based on different concepts about nested relation.…”

Section: An Evaluation Of Normal Forms For Nested Relationsmentioning

confidence: 99%

“…These normal forms are proposed based on different concepts about nested relation. In this section, we evaluate three normal forms, NF-NR, whose predecessor is the NF-N3 in [9], NF, proposed in [11] and NNF, proposed in [12]. One interesting question is: what is the criteria based on which we can say that a normal form is "good"?…”

Section: An Evaluation Of Normal Forms For Nested Relationsmentioning

confidence: 99%

“…These anomalies must be removed by a normal form. In [11,12,13,9], normal forms for nested relations are discussed. These normal forms are based on their own conceptualizations of the model of nested relation and the real world application to be modeled.…”

Section: Introductionmentioning

confidence: 99%

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NF-NR: A practical normal form for nested relations

Ling

Yan

1994

Journal of Systems Integration

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We propose a normal form for nested relations, called NF-NR, which Two approaches to NF-NR database design, namely the restructuring rules approach and the ER approach, are discussed. We relate NF-NR to ER-NF, a normal form of ER defined earlier, by defining a simple mapping from an ERD in ER-NF to a set of nested relations in NF-NR. This approach effectively removes ambiguities and redundancies on a semantic level and hence gives a set of nested relations with clean semantics and yet in good normal form. A set of desirable properties for any normal form for nested relations are described and an evaluation of several existing normal forms isgiven based on this set of properties. The evaluation shows that NF-NR improves over previously proposed normal forms in various aspects and is a more practical normal form for nested relations.

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Section: Property 1: Normal Form For Nested Relations Should Reduce Tmentioning

confidence: 98%

Section: Property 2: a Normalized Nested Relation Can Be Represented mentioning

confidence: 99%

“…Several normal forms for nested relations were proposed [11,12,9]. These normal forms are proposed based on different concepts about nested relation.…”

Section: An Evaluation Of Normal Forms For Nested Relationsmentioning

confidence: 99%

Section: An Evaluation Of Normal Forms For Nested Relationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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NF-NR: A practical normal form for nested relations

Ling

Yan

1994

Journal of Systems Integration

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Temporal Databases

Tansel¹

2008

Wiley Encyclopedia of Computer Science and Engineering

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A temporal database stores time‐varying data and has the capabilities to manipulate it. Two commonly used time dimensions for maintaining temporal data are valid time and transaction time. Temporal databases are classified as valid time, transaction time, or bitmeporal databases. Temporality in databases involve subtle issues like comparing database states at different times, temporal grouping, different ways to represent the same temporal data, consistency of the timestamps of different attributes, temporal integrity constraints, and designing temporal databases. A temporal atom is a timestamp and value pair in which The timestamp is valid and/or transaction time and value are the time‐varying data. For representing and manipulating temporal data, data models handle temporal atoms differently. In relational data model, which is the focus of this entry, attribute or tuple time stamping may be used. Temporal algebra and temporal calculus languages are defined accordingly. Proposals for extending SQL2 for temporal data manipulation exist, and SQl3 supports user‐defined data types that can be used for defining and manipulating temporal data. This entry covers temporal query languages and the temporal issues mentioned above.

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Resource Space Grid: model, method and platform

Zhuge

2004

Concurrency and Computation

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SUMMARYA Resource Space Grid is a virtual Grid that aims at effectively sharing, using and managing versatile resources across the Internet. The kernel of the Resource Space Grid includes a Resource Space Model (RSM) and a uniform Resource Using Mechanism (RUM). This paper presents the Resource Space Grid's core scientific issues and methodology, architecture, model and theory, design criteria and method, and practice. A normal form theory is proposed to normalize the resource space-a coordinate system for uniformly specifying and organizing resources. The RUM provides not only the end-users with an operable resource browser to operate resources using the built-in Resource Operation Language (ROL), but also the application developers with the ROL-based programming environment. The prototype platform based on the proposed model and method has been implemented and used for sharing and managing resources in distributed research teams. Operations on Resource Spaces can constitute the virtual communities of Resource Space Grids-a platform independent resource sharing environment.

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A new normal form for nested relations

Cited by 126 publications

References 17 publications

NF-NR: A practical normal form for nested relations

NF-NR: A practical normal form for nested relations

Temporal Databases

Resource Space Grid: model, method and platform

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