Finding the Transitive Closure of Functional Dependencies using Strategic Port Graph Rewriting

Varga, János

doi:10.4204/eptcs.288.5

Cited by 3 publications

(6 citation statements)

References 15 publications

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“…Transitivity Strategy: This strategy, without the calls to the Augmentation strategy in line 17 and line 23, was shown to be terminating in [27]. We use the same measures, since they are not affected by the call to the Augmentation strategy: For repeat(one(T ransitivity k ); #Augmentation#), the measure is the number of possible matches of the LHS subgraph of f1.…”

Section: Discussionmentioning

confidence: 99%

“…This design decision is based on the separation of concerns principle. The Functional Dependency Port Graph (FDPGs) [27] is a particular case of the above defined Database Port Graph, with Attribute and FD nodes only. An example FDPG is given in Figure 10 in Appendix E.…”

Section: Definition 3 (Relational Database Port Graph Vdsl Rdpg-vdsl)mentioning

confidence: 99%

“…To deal with functional dependencies of various arities, previous works used multiple rules [27] or internal data structures (e.g. compound node in [5]).…”

Section: Variadic Rewriting Rulesmentioning

confidence: 99%

“…Transitivity. A family of Transitivity rules was described in [27] to detect transitive functional dependency chains f 1 : X → Y and f 2 : Y → A. Instead, here we provide a compact representation of the transitivity axiom in the form of a variadic rule, shown in Figure 5.…”

Section: Rewriting Rulesmentioning

confidence: 99%

“…Our contribution and main difference with respect to these works is the design of a domain-specific visual language with emphasis on interactive modelling, including strategies to control the application of rules, and the use of the derivation tree as part of the visualisation framework, giving the modeller access to all the sequences of transformation steps, to facilitate the analysis of the system. Port graphs were used to compute transitive closures in [27]. Here we compute the full Armstrong closure (not just transitive closure), and show how to use the derivation tree to analyse closures and answer queries about the database model, such as whether a given functional dependency is in the closure of a set of dependencies (the membership problem), and compute minimal covers.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A Port Graph Rewriting Approach to Relational Database Modelling

Fernández

Pinaud

Varga

2020

Logic-Based Program Synthesis and Transformation

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We present new algorithms to compute the Syntactic Closure and the Minimal Cover of a set of functional dependencies, using strategic port graph rewriting. We specify a Visual Domain Specific Language to model relational database schemata as port graphs, and provide an extension to port graph rewriting rules. Using these rules we implement strategies to compute a syntactic closure, analyse it and find minimal covers, essential for schema normalisation. The graph program provides a visual description of the computation steps coupled with analysis features not available in other approaches. We prove soundness and completeness of the computed closure. This methodology is implemented in PORGY.

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Section: Discussionmentioning

confidence: 99%

Section: Definition 3 (Relational Database Port Graph Vdsl Rdpg-vdsl)mentioning

confidence: 99%

“…To deal with functional dependencies of various arities, previous works used multiple rules [27] or internal data structures (e.g. compound node in [5]).…”

Section: Variadic Rewriting Rulesmentioning

confidence: 99%

Section: Rewriting Rulesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Port Graph Rewriting Approach to Relational Database Modelling

Fernández

Pinaud

Varga

2020

Logic-Based Program Synthesis and Transformation

Self Cite

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A Strategic Graph Rewriting Model of Rational Negligence in Financial Markets

Ene

Fernández

Pinaud

2020

Springer Proceedings in Mathematics &Amp; Statistics

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We propose to use strategic port graph rewriting as a visual modelling tool to analyse financial market processes. We illustrate the approach by specifying a basic "rational negligence" model in which investors may choose to trade securities without performing independent evaluations of the underlying assets. We show that our model is correct with respect to the equational model and can be used to simulate simple market behaviours. The model has been implemented within PORGY, a graph-based specification and simulation environment.

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Category-Based Administrative Access Control Policies

Bertolissi,

Fernandez,

Thuraisingham

2024

ACM Trans. Priv. Secur.

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As systems evolve, security administrators need to review and update access control policies. Such updates must be carefully controlled due to the risks associated with erroneous or malicious policy changes. We propose a category-based access control (CBAC) model, called Admin-CBAC , to control administrative actions. Since most of the access control models in use nowadays (including the popular RBAC and ABAC models), are instances of CBAC, from Admin-CBAC we derive administrative models for RBAC and ABAC too. We present a graph-based representation of Admin-CBAC policies and a formal operational semantics for administrative actions via graph rewriting. We also discuss implementations of Admin-CBAC exploiting the graph-based representation. Using the formal semantics, we show how properties (such as safety, liveness and effectiveness of policies) and constraints (such as separation of duties) can be checked, and discuss the impact of policy changes. Although the most interesting properties of policies are generally undecidable in dynamic access control models, we identify particular cases where reachability properties are decidable and can be checked using our operational semantics, generalising previous results for RBAC and ABAC α .

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Finding the Transitive Closure of Functional Dependencies using Strategic Port Graph Rewriting

Cited by 3 publications

References 15 publications

A Port Graph Rewriting Approach to Relational Database Modelling

A Port Graph Rewriting Approach to Relational Database Modelling

A Strategic Graph Rewriting Model of Rational Negligence in Financial Markets

Category-Based Administrative Access Control Policies

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