Answering XML Twig Queries with Automata

Sun, Bing; Zhang, Bo; Tang, Nan; Wang, Guoren; Yu, Ge; Jia, Fulin

doi:10.1007/978-3-540-24655-8_18

Cited by 2 publications

(12 citation statements)

References 2 publications

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“…can be built as follows: 1) evaluate the two strict queries Chnq1 = l1/.../lm and Chnq2 = l1/.../lm/l(m+1) on the DataGuide. Let's note α =[a0,..., am] and β =[b1,..., bn] the corresponding answers 9 . 2) initialize Tnq to β: Tnq =[b1,..., bn].…”

Section: Evaluating a Prefpathquery On An Annotated Dataguidementioning

confidence: 99%

“…Following the presentation in section 3.2.1, the list associated with the query node A/B! is TB =[ε0 (1,9), ε1(10, 11), b1, ε2 (13,15), ε3 (15,16), ε4 (16,17), b2] where, the εi, i = 0,..., 4 are the pseudo occurrences of B. The lists associated with the respective nodes A, C and /A/D/E are respectively: TA =[a1, a2, a3], TC =[c1, c2, c3, c4, c5], TE =[e1, e2, e3].…”

Section: Preftwigstack: the Best Answers Merging Phasementioning

confidence: 99%

“…Several approaches to evaluate such queries have already been proposed in the literature (see section 2.2). They usually differ by the document indexing technique used (like DataGuide [7] or region encoding [8]) or by their evaluation strategy (like rewriting queries before their evaluation, [9,7,8] or direct evaluation [10]). We propose in this paper an approach to evaluate queries with structural preferences.…”

Section: Introductionmentioning

confidence: 99%

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Holistic Evaluation of XML Queries With Structural Preferences on an Annotated Strong Dataguide

Tchendji¹,

Nkuefone²,

Tchendji³

2019

IJSEA

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With the emergence of XML as de facto format for storing and exchanging information over the Internet, the search for ever more innovative and effective techniques for their querying is a major and current concern of the XML database community. Several studies carried out to help solve this problem are mostly oriented towards the evaluation of so-called exact queries which, unfortunately, are likely (especially in the case of semi-structured documents) to yield abundant results (in the case of vague queries) or empty results (in the case of very precise queries). From the observation that users who make requests are not necessarily interested in all possible solutions, but rather in those that are closest to their needs, an important field of research has been opened on the evaluation of preferences queries. In this paper, we propose an approach for the evaluation of such queries, in case the preferences concern the structure of the document. The solution investigated revolves around the proposal of an evaluation plan in three phases: rewriting-evaluation-merge. The rewriting phase makes it possible to obtain, from a partitioningtransformation operation of the initial query, a hierarchical set of preferences path queries which are holistically evaluated in the second phase by an instrumented version of the algorithm TwigStack. The merge phase is the synthesis of the best results.

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Section: Evaluating a Prefpathquery On An Annotated Dataguidementioning

confidence: 99%

Section: Preftwigstack: the Best Answers Merging Phasementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Holistic Evaluation of XML Queries With Structural Preferences on an Annotated Strong Dataguide

Tchendji¹,

Nkuefone²,

Tchendji³

2019

IJSEA

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“…A cet effet, nous proposons le langage PrefSXPath, une extension du langage XPath permettant d'exprimer les requêtes XPath avec préférences structurelles. Bien plus, nous présentons aussi une approche d'évaluation des requêtes PrefSXPath à l'aide des automates suivant la technique utilisée par Bin Sun et al [2] pour l'évaluation des requêtes classiques (sans préférences). Notons que notre proposition se distingue de celles de [14,11] sur bien des points : ils se sont intéressés principalement aux préférences portant sur les valeurs quand nous le faisons sur les structures, leur extension de XPath est localisée au niveau des prédicats alors que la notre porte également sur des noeuds sans prédicats ; là où ils font une réécriture de requête nous proposons un algorithme d'évaluation.…”

Section: Introductionunclassified

“…La figure 1 donne une vue synoptique de la démarche d'évaluation proposée ; elle se décline en deux étapes. En fait, étant donné une requête PrefSXPath Q à appliquer à un document XML D, après construction comme dans [2] d'un automate A relativement à la requête Q et extraction d'un index T q de D, dans la première étape, A est utilisé pour générer toutes les réponses de Q dans D sans tenir compte des préférences. Parallèlement à la production des réponses de cette étape, des structures de données contenant des informations pour la sélection des meilleures réponses sont produites et utilisées dans la seconde étape pour construire une table relationnelle preferenceTable.…”

Section: Introductionunclassified

XPath bipolar queries and evaluation

Nguefack

Tchendji

2017

Revue Africaine De Recherche en Informatique Et Mathématiques Appliquées

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The concept of bipolar queries (also call preferences queries) emerged in the Relational Databasescommunity, allowing users to get much more relevant responses to their requests, expressed via queries say withpreferences. Such requests usually have two parts: the first is used to express the strict constraints and thesecond, preferences or wishes. Any response to a query with preferences must necessarily satisfy the first partand preferably the latter. However, if there is at least a satisfactory answer of the second part, those satisfyingonly the first part will be excluded from the final result: they are dominated. In this paper, we explore an approachof importation of this concept in a XML Database via XPath language. To do this, we propose PrefSXPathlanguage, an extension of XPath in order to express XPath queries with structural preferences, then we presenta query evaluation algorithm of PrefSXPath using automata Le concept de requêtes bipolaires (on parle aussi de requêtes avec préférences) a émergé dans la communauté des Bases de Données Relationnelles, pour permettre aux utilisateurs d'obtenir des réponses beaucoup plus pertinentes à leurs préoccupations, exprimées via des requêtes dites avec préférences. De telles requêtes ont généralement deux parties : la première permet d'exprimer les contraintes strictes et la seconde, des préférences ou souhaits. Toute réponse à une requête avec préférences doit nécessairement satisfaire la première partie et préférentiellement la seconde. Toutefois, s'il existe au moins une réponse satisfaisant la seconde partie, toutes les réponses ne satisfaisant que la première partie seront exclues du résultat final : elles sont dominées. Dans ce papier, nous explorons une approche d'importation de ce concept dans les Bases de Données XML via le langage XPath. Pour ce faire, nous proposons le langage PrefSXPath, une extension du langage XPath permettant d'exprimer les requêtes XPath avec préférences structurelles, puis, nous présentons un algorithme d'évaluation des requêtes PrefSXPath à l'aide des automates. ABSTRACT. The concept of bipolar queries (also call preferences queries) emerged in the Relational Databases community, allowing users to get much more relevant responses to their requests, expressed via queries say with preferences. Such requests usually have two parts: the first is used to express the strict constraints and the second, preferences or wishes. Any response to a query with preferences must necessarily satisfy the first part and preferably the latter. However, if there is at least a satisfactory answer of the second part, those satisfying only the first part will be excluded from the final result: they are dominated. In this paper, we explore an approach of importation of this concept in a XML Database via XPath language. To do this, we propose PrefSXPath language, an extension of XPath in order to express XPath queries with structural preferences, then we present a query evaluation algorithm of PrefSXPath using automata.

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Answering XML Twig Queries with Automata

Cited by 2 publications

References 2 publications

Holistic Evaluation of XML Queries With Structural Preferences on an Annotated Strong Dataguide

Holistic Evaluation of XML Queries With Structural Preferences on an Annotated Strong Dataguide

XPath bipolar queries and evaluation

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