Declarative Access to Filesystem Data : New application domains for XML database management systems

Holupirek, Alexander

Declarative Access to Filesystem Data : New application domains for XML database management systems

Files

Diss_Holupirek_Declarative_Access_to_Filesystem_Data.pdf(6.4 MB)

Date

2012

Project

BaseX – Processing and Visualizing large XML Instances
XQuery Your Filesystem - Enhancing filesystems using semi-structured database technology

Collections

Informatik und Informationswissenschaft

Publication type

Dissertation

Abstract

XML and state-of-the-art XML database management systems (XML-DBMSs) can play a leading role in far more application domains as it is currently the case.

Even in their basic configuration, they entail all components necessary to act as central systems for complex search and retrieval tasks. They provide language-specific indexing of full-text documents and can store structured, semi-structured and binary data.

Besides, they offer a great variety of standardized languages (XQuery, XSLT, XQuery Full Text, etc.) to develop applications inside a pure XML technology stack. Benefits are obvious: Data, logic, and presentation tiers can operate on a single data model, and no conversions have to be applied when switching in between.

This thesis deals with the design and development of XML/XQuery driven information architectures that process formerly heterogeneous data sources in a standardized and uniform manner. Filesystems and their vast amounts of different file types are a prime example for such a heterogeneous dataspace. A new XML dialect, the Filesystem Markup Language (FSML), is introduced to construct a database view of the filesystem and its contents. FSML provides a uniform view on the filesystem’s contents and allows developers to leverage the complete XML technology stack on filesystem data.

BaseX, a high performance, native XML-DBMS developed at the University of Konstanz, is pushed to new application domains. We interface the database system with the operating system kernel and implement a database/filesystem hybrid (BaseX-FS), which is working on FSML database instances. A joint storage for both the filesystem and the database is established, which allows both developers and users to access data via the conventional and proven filesystem interface and, in addition, through a novel declarative, database-supported interface. As a direct consequence, XML languages such as XQuery can be used by applications and developers to analyze and process filesystem data. Smarter ways for accessing personal information stored in filesystems are achieved by retrieval strategies with no, partial, or full knowledge about the structure, format, and content of the data (“Query the filesystem like a database”).

In combination with BaseX-Web, a database extension that facilitates the development of desktop-like web applications, we present a system architecture that makes it easier for application developers to build content-oriented (data-centric) retrieval and search applications dealing with files and their contents. The proposed architecture is ready to drive (expert) information systems that work with distinct data sources, using an XQuery-driven development approach. As a concluding proof of concept, a complete development cycle for an OPAC (Online Public Access Catalogue) system is presented in detail.

Summary in another language

XML einerseits und moderne XML-Datenbank-Management-Systeme (XML-DBMS) andererseits können als Basistechnologie weit mehr leisten, als ihnen derzeit zugetraut wird.

Bereits in ihrer Grundausstattung beinhalten sie alle notwendigen Komponenten, die für den Aufbau und den Betrieb komplexer Such- und Informationsdienste notwendig sind. Der Umgang mit Volltexten und deren sprachspezifische Indexierung gehört ebenso zu den Aufgaben eines modernen XML-DBMSs wie die Speicherung von strukturierten, semi-strukturierten oder binären Daten.

Sie verfügen über ein reichhaltiges Arsenal an XML verarbeitenden Sprachen (XQuery, XSLT, XQuery Full Text, etc.) und bieten damit einen kompletten Technologiezweig an, der es erlaubt, innerhalb einer reinen, also nur auf XML Technologie basierenden Umgebung Applikationen zu entwickeln. Die Vorteile liegen auf der Hand: Von der Speicherung über die Verarbeitung bis hin zur Ergebnispräsentation kann das gleiche Datenmodell ohne Transformation zwischen den einzelnen Schichten einer Systemarchitektur erfolgen.

Die vorliegende Arbeit erprobt die Verwendung von XML-DBMSs auf bisher unbekanntem Terrain und untersucht deren Einsatzmöglichkeiten innerhalb moderner Betriebssysteme.

Wir zeigen, wie über den Einsatz von XML-DBMSen eine deklarative Schnittstelle zur Abfrage von Dateisystem-Inhalten mittels XQuery geschaffen werden kann und implementieren ein hybrides Datenbankdateisystem (BaseX-FS). Die Technologiestudie erlaubt es, auf den Daten des Dateisystems, sowohl konventionell, also über die vom Betriebsystem angebotenen system calls und den filesystem namespace, zu arbeiten, als auch mit Hilfe der vom Datenbanksystem angebotenen deklarativen Zugriffsmethoden.

Das heisst insbesondere, dass die in BaseX-FS gespeicherten Dateien semantisch und inhaltsbezogen über XQuery abgerufen und verarbeitet werden können, als auch, dass über die Verzeichnishierarchie inhaltsbezogene Daten einer Datei exportiert und mit konventionellem File I/O bearbeitet werden können.

Unter Verwendung von BaseX-FS als Basisarchitektur lässt sich zeigen, dass zahlreiche Dienste, wie zum Beispiel Desktopsuchmaschinen sehr viel leichtgewichtiger implementiert und funktional erweitert werden können, als dies bisher der Fall ist.

Zusammen mit BaseX-Web, einer Datenbankerweiterung, die es erlaubt, desktop-ähnliche Web-Applikationen zu entwickeln, zeigen wir, dass sich die vorgestellte erweiterte Datenbankarchitektur sehr gut für den Aufbau von Expertensuchsystemen, wie zum Beispiel eines Online Public Access Catalogues (OPAC), eignet.

Subject (DDC)

004 Computer Science

Cite This

ISO 690

HOLUPIREK, Alexander, 2012. Declarative Access to Filesystem Data : New application domains for XML database management systems [Dissertation]. Konstanz: University of Konstanz

BibTex

@phdthesis{Holupirek2012Decla-20648,
  year={2012},
  title={Declarative Access to Filesystem Data : New application domains for XML database management systems},
  author={Holupirek, Alexander},
  address={Konstanz},
  school={Universität Konstanz}
}

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Examination date of dissertation

July 17, 2012

Bibliography of Konstanz

Yes