Magistro darbo tema – Transformavimo operatoriai pusiau struktūrizuotų (XML) duomenų bazių užklausų kalbose. Yra nustatoma tyrimui naudojama užklausų kalba – XQuery. Detaliai aprašoma informacija susijusi su užklausų kalba ir informacija, kuri bus naudojama XQuery užklausų kalbos transformavimo operatorių (šiame darbe – funkcijų) kūrime, bei tyrime. Pasinaudojama formaliu modeliu pasiūlytu „Université de Toulon et du Var“ universiteto tyrimo grupės [BMM03]. Yra sukuriamos keturios funkcijos : transf_insert, transf_delete, transf_replace, transf_move. Toliau yra sukuriamas XML dokumentas, kuris bus naudojamas tyrime t.y. palyginime tarp sukurtų XQuery funkcijų, bei XSLT transformacijų. Tyrimas yra atliekamas lyginant kiekvieną sukurtą funkciją su XSLT transformacijomis po du kartus. Pirmą kartą yra lyginama transformacija su elementu, o antrą kartą su elementu ir požymiu. Antrame tyrime yra naudojamos automatiškai sugeneruotos XML struktūros, kurios skiriasi medžio ilgiu, gyliu ir galutiniu dokumento dydžiu. Yra lyginamos transformacijos su elementu ir požymiu šiem dokumentam. Galiausiai yra pristatomos išvados ir rezultatai, kuriuose yra pasiūloma kaip ir kada galima būtų naudoti naujai sukurtas funkcijas ir kada galima būtų naudoti XSLT transformacijas. / This document is about the transformation operators in semi-structured (XML) database query languages. XQuery is chosen as a query language to be used for research. A detailed description of the information related to the query language and information that will be used for development and investigation of XQuery transformation operators (in this work – functions) is provided. The formal model of transformation operators that was created by „Université de Toulon et du Var“ university research group [BMM03] is used in this work. We create four functions (named: transf_insert, transf_delete, transf_move, transf_replace) and an XML document. The document is used in the comparison between new XQuery functions and the XSLT transformation. The comparison is executed twice for each of the functions: first, for elements only and then for the same elements along with their attributes. The second part of the research is performed on different XML documents that are automatically generated and their structure differs in tree length, tree depth and resulting size of the document. Finally, conclusions and results are being introduced. It is concluded in which situations which technology should be preferred to use – either XQuery or XSLT transformations.

XML distribuées basées sur les réseaux pair-à-pair. Notre approche est unique parce qu'elle est axée sur le traitement global du langage XQuery plutôt que l'étude d'un langage réduit spécifique aux index utilisés. Le système XQ2P présenté dans cette thèse intègre cette architecture ; il se présente comme une collection complète de blocs de logiciels fondamentaux pour développer des applications similaires. L'aspect pair-à-pair est fourni par P2PTester, un " framework " fournissant des modules pour les fonctionnalités P2P de base et un système distribué pour des tests et simulations. Une version de l'algorithme TwigStack adapté au P2P, utilisant un index structurel basé sur le numérotage des noeuds, y est intégré. Avec le concours d'un système de pré-traitement des requêtes il permet à XQ2P l'évaluation efficace des requêtes structurelles sur la base de données distribuée. Une version alternative du même algorithme est aussi utilisée pour l'évaluation efficace de la plupart des requêtes en langage XQuery. L'une des nouveautés majeures de XQuery 3.0 est l'étude des séries temporelles. Nous avons défini un modèle pour traiter ce type de données, utilisant le modèle XML comme représentation des valeurs et des requêtes XQuery 3.0 pour les manipuler. Nous ajoutons à XQ2P un index adapté à ce modèle ; le partitionnement horizontal des longues séries de données chronologiques, des opérateurs optimisés et une technique d'évaluation parallèle des sous-expressions permettent l'exécution efficace d'opérations avec des volumes de données importants.

Since the World Wide Web Consortium (W3C) has recommended XQuery as the standard XML query language, the interest in using existing relational technology to query the XML data has dramatically increased. The most significant challenge of the relational approach is how to fully support XQuery semantics in XQuery-to-SQL translation. To eliminate the implicit semantics of XQuery, an XQuery fragment must be defined with simple syntax and explicit semantics. XQ is proposed as an XQuery fragment to express XML queries. <br /><br /> In this thesis, XQ is intensively investigated. It is encoded by <em>System F</em>, a second-order lambda calculus with a considerable expressive power and a strong normalization property. Since XML data is defined as inductive data types, XML tree and XML forest, in <em>System F</em>, all basic XML operators in XQ have been successfully encoded. Also, the semantics of XQ are represented in <em>System F</em> where XQ's semantics environment is encoded by an <em>Environment</em> data type with the corresponding operators. The successful encoding of XQ by <em>System F</em> ensures the termination of XQ query evaluation. <br /><br /> Moreover, an extension of XQ by a new tree operator Xtree and a vertical Vfor clause is proposed in this thesis to express some <em>undefinable</em> XQ queries. It is demonstrated that this extension still allows XQ to retain its XQ-to-SQL translation property that ensures the polynomial evaluation time complexity, and its <em>System F</em> encodable property that ensures the termination of query evaluation.

Since the World Wide Web Consortium (W3C) has recommended XQuery as the standard XML query language, the interest in using existing relational technology to query the XML data has dramatically increased. The most significant challenge of the relational approach is how to fully support XQuery semantics in XQuery-to-SQL translation. To eliminate the implicit semantics of XQuery, an XQuery fragment must be defined with simple syntax and explicit semantics. XQ is proposed as an XQuery fragment to express XML queries. <br /><br /> In this thesis, XQ is intensively investigated. It is encoded by <em>System F</em>, a second-order lambda calculus with a considerable expressive power and a strong normalization property. Since XML data is defined as inductive data types, XML tree and XML forest, in <em>System F</em>, all basic XML operators in XQ have been successfully encoded. Also, the semantics of XQ are represented in <em>System F</em> where XQ's semantics environment is encoded by an <em>Environment</em> data type with the corresponding operators. The successful encoding of XQ by <em>System F</em> ensures the termination of XQ query evaluation. <br /><br /> Moreover, an extension of XQ by a new tree operator Xtree and a vertical Vfor clause is proposed in this thesis to express some <em>undefinable</em> XQ queries. It is demonstrated that this extension still allows XQ to retain its XQ-to-SQL translation property that ensures the polynomial evaluation time complexity, and its <em>System F</em> encodable property that ensures the termination of query evaluation.

De nos jours, l'importance sans cesse croissante des masses de données conduit les <br />décideurs de divers domaines à faire appel aux techniques d'Extraction de Connaissances <br />à partir des Données (ECD). L'une des étapes principales de ce processus est la fouille <br />de données. Or, interpréter les résultats issus de ces méthodes de fouille de données, <br />en particulier pour les méthodes de classication automatique, reste complexe pour les <br />utilisateurs. Ce qui rend indispensable l'utilisation d'une nouvelle approche permettant <br />d'aider les utilisateurs à interpréter automatiquement leurs résultats. Ainsi, nous propo- <br />sons une nouvelle approche, appelée AIMFD (Approche d'Incorporation de Métadonnées <br />dans la Fouille de Données) qui se résume principalement à intégrer des informations <br />sémantiques (métadonnées) permettant d'aider les utilisateurs à interpréter de manière <br />automatique les résultats des méthodes de fouille de données. Nous appliquons cette ap- <br />proche au domaine de la classication automatique.

Techn. University, Diss., 2007--Darmstadt.

Konstanz, Univ., Diplomarb., 2003.

Updating XML data is very wide area, which must solve a number of difficult problems. From designing language with sufficient expressive power to the XML data repository able to apply the changes. Ways to deal with them are few. From this perspective, is this work very closely dedicated only to the language XQuery. Thus, its extension for updates, for which the candidate recommendation by the W3C were published only recently. Another specialization of this work is to focus only on the XML data stored in the object­relational database with that repository will enforce the validity of documents to the scheme described in XML Schema. This requirement, combined with the possibility of updating of data in the repository is on the contradictory requirements. In this thesis is designed language based on XQuery language, designed and implemented evaluating of the update queries of the language on the store and a description and implementation of the store in object­relational database.

"Keeping views fresh by maintaining the consistency between materialized views and their base data in the presence of base updates is a critical problem for many applications, including data warehousing and data integration. While heavily studied for traditional databases, the maintenance of XML views remains largely unexplored. Maintaining XML views is complex due to the richness of the XML data model and the powerful capabilities of XML query languages, such as XQuery. This dissertation proposes a comprehensive solution for the general problem of maintaining materialized XQuery views. Our solution is the first to enable the maintenance of a large class of XQuery views including XPath expressions, FLWOR expressions, and Element Constructors. These views may contain arbitrary result construction and arbitrary grouping and join operations. Our solution also supports the unique order requirements of XQuery including source document order and query order. The contributions of this dissertation include: (i) an efficient solution for supporting order in XML query processing and view maintenance, (ii) an identifier-based technique for enabling incremental construction of XML views, (iii) a mechanism for modeling and validating source XML updates, (iv) a counting algorithm for supporting view maintenance on delete and modify updates, (v) an algebraic solution for propagating bulk XML updates, and (vi) an efficient mechanism for refreshing materialized XML views on propagated updates. We provide proofs of correctness of our proposed techniques for materialized XQuery maintenance. We have implemented a prototype of our view maintenance solution on top of the Rainbow XML query engine, developed at WPI. Our experiments confirm that our solution provides a practical and efficient solution for maintaining materialized XQuery views even when handling heterogeneous batches of possibly large source updates. Our solution follows the widely adopted propagate-apply framework for view maintenance common to all mainstream query engines. That is, our solution produces incremental maintenance plans in the same algebraic language used to define the views. These plans can thus be optimized and executed by standard query processing techniques. Being compatible with standard frameworks paves the way for our XML view maintenance solution to be easily adopted by existing database engines."

"Update operations over XML views are essential for applications using XML views. In this dissertation work, we provide scalable solutions to support updating through XML views defined over relational databases. Especially we focus on the update-public semantic, where updates are always public (made to the public database), and the update-local semantic, where update effects are first kept local and then made public as and when required. Towards this, we propose the clean extended-source theory for determining whether a correct view update translation exists, which then serves as a theoretical foundation for us to design practical XML view updating algorithms. Under update-public semantic, state-of-the-art view updating work focus on identifying the correct update translation purely on the data. We instead take a schema-centric solution, which utilizes the schema of the underlying source to effectively prune updates that are guaranteed to be not translatable and pass updates that are guaranteed to be translatable directly to the SQL engine. Only those updates that could not be classified using schema knowledge are finally analyzed by examining the data. This required data-level check is further optimized under schema guidance to prune the search space for finding a correct translation. As the first work addressing the update-local semantic, we propose a practical framework, called LoGo. LoGo Localizes the view update translation, while preserves the properties of views being side-effect free and updates being always updatable. LoGo also supports on-demand merging of the local database of the subject viewinto the public database (also called global database), while still guaranteeing the subject view being free of side effects. A flexible synchronization service is provided in LoGo that enables all other views defined over the same public database to be refreshed, i.e., synchronized with the publically committed changes, if so desired. Further, given that XMLis an ordered datamodel,we propose an ordersensitive solution named O-HUX to support XML view updating with order. We have implemented the algorithms, along with respective optimization techniques. Experimental results confirm the effectiveness of the proposed services, and highlight its performance characteristics."