P026 - BTW 2003 – Datenbanksysteme für Business, Technologie und Web
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- KonferenzbeitragThe IOP approach to enterprise frameworks(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Nink, Udo; Schäfer, StefanThis paper introduces the Internet Operating Platform (IOP), an enterprise framework for large scale software development. In addition to obeying to important standards (UML, XML, Java) an enterprise framework has to fulfil three basic requirements. First of all, it has to be broad and needs an elaborate architecture complementing standards and technologies rather than purely connecting them. Therefore, IOP combines UML modeling, workflow specification, code generation, run-time configuration, and component architectures. Secondly, an enterprise framework allows most developers to concentrate on business leaving technical issues to a few specialists. Therefore, IOP abstracts from underlying technologies in the areas of front-ends (HTML, XML, Java), communication protocols (FTP, HTTP, JMS, RMI), distributed components (EJB, CORBA), and persistence (virtual memory, XML, SQL92, SQL:1999). All corresponding drivers are replaceable and can even coexist. Third, an enterprise framework has to provide micro solutions on both technical and business levels. Thus, IOP provides amongst others built-in services and components like session management on a technical level and content management on a business level.
- KonferenzbeitragXML in der oracle datenbank „relational and beyond"(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Schwinn, UlrikeIn Geschäfts- und B2B-Anwendungen wird XML zunehmend als das Format für elektronisches Publizieren und den Austausch von Dokumenten eingesetzt. Richtiges Speichern von XML-Dokumenten ist dabei ein viel diskutiertes Thema. So werden beispielsweise beim nicht nativen Speichern Webinhalte und Applikationsdaten entweder in relationalen Tabellen, im Dateisystem oder in beidem gespeichert. Die besonderen Merkmale von XML können dabei jedoch nicht berücksichtigt werden. Bei großen Mengen von Austauschdaten stellt sich überhaupt die Frage, ob diese Speicherungsform XML-Applikationen überhaupt gerecht werden kann. Eine gute Lösung bieten hingegen die so genannten nativen XML-Datenbanken. In diesem Artikel wird am Beispiel des neuesten Oracle-Datenbank-Release das Konzept einer nativen XML-Datenbank vorgestellt.
- KonferenzbeitragManipulation von XML-Dokumenten in Tamino(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Gesmann, MichaelDieser Beitrag untersucht die Frage, wie XML-Dokumente, die in Datenbanksystemen abgespeichert sind, effektiv und effizient innerhalb dieser Systeme verändert werden können. Zunächst wird skizziert, welche Lösungsansätze bereits existieren. Danach wird erläutert, wie dieses Problem in der neuen Version des XML-Datenbanksystems Tamino von der Software AG gelöst wird. Dort wird ein sprachbasierter Ansatz auf der Basis von XQuery-Erweiterungen verfolgt.
- KonferenzbeitragXpath-aware chunking of XML-documents(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Lehner, Wolfgang; Irmert, FlorianDissemination systems are used to route information received from many publishers individually to multiple subscribers. The core of a dissemination system consists of an efficient filtering engine deciding what part of an incoming message goes to which recipient. Within this paper we are proposing a chunking framework of XML documents to speed up the filtering process for a set of registered subscriptions based on XPath expressions. The problem which will be leveraged by the proposed chunking scheme is based on the observation that the execution time of XPath expressions increases with the size of the underlying XML document. The proposed chunking strategy is based on the idea of sharing XPath prefixes among the query set additionally extended by individually selected nodes to be able to handle XPath-filter expressions. Extensive tests showed substantial performance gains.
- KonferenzbeitragOraGiST - How to make user-defined indexing become usable and useful(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Kleiner, Carsten; Lipeck, Udo W.In this article we present a concept for simplification of user-defined indexing for user-defined data types in object-relational database systems. The concept is based on a detailed analysis of user-defined indexing in ORDBS on one hand, and features of generalized search trees (GiST) as an extensible indexing framework on the other hand. It defines a minimal interface to be implemented in order to use GiST within ORDBS; this greatly simplifies the process of implementing user-defined indexes. The effectiveness of the approach is illustrated by performance experiments carried out on a prototypical implementation of our concept. For the experiments we have used new specialized spatial data types, that store spatial as well as thematic information within a single attribute. These data types facilitate advanced spatial analysis operators. The experiments show great performance improvements on these operators by using multidimensional user-defined index structures based on R-trees when compared to system-provided indexes.
- KonferenzbeitragTransbase®: A leading-ege ROLAP engine supporting multidimentstional indexing and hierarchy clustering(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Pieringer, R.; Elhardt, K.; Ramsak, F.; Markl, V.; Fenk, R.; Bayer, R.Analysis-oriented database applications, such as data warehousing or customer relationship management, play a crucial role in the database area. In general, the multidimensional data model is used in these applications, realized as star or snow-flake schemata in the relational world. The so-called star queries are the prevalent type of queries on such schemata. All database vendors have extended their products to support star queries efficiently. However, mostly reporting queries benefit from the optimizations, like pre-aggregation, while ad-hoc queries usually lack efficient support. We present the DBMS Transbase® in this paper, which provides a new physical organization of the data based on hierarchical clustering and multidimensional clustering combined with multidimensional indexing. In combination with new query optimizations (e.g., hierarchical pre-grouping) significant performance improvements are achieved. The paper describes how the new technology is implemented in the Transbase® product and how it is made available to the user as transparently as possible. The benefits are illustrated with a real-world data warehousing scenario.
- KonferenzbeitragExecuting nested queries(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Graefe, GoetzOptimization of nested queries, in particular finding equivalent "flattened" queries for queries that employ the SQL sub-query construct, has been researched extensively. In contrast, with the exception of nested loops join, execution of nested plans has found little interest. Nested execution plans may result from a failure to flatten nested SQL expressions but just as likely are created by a query optimizer to exploit all available indexes as effectively as possible. In fact, if materialized views and index tuning perform as expected, few queries should require large operations such as parallel scans, sorts and hash joins, and most actual query plans will rely entirely on navigating indexes on tables and views. Note that only index navigation plans scale truly gracefully, i.e., perform equally well on large and on very large databases, whereas sorting and hashing scale at best linearly. Since a typical index navigation plan employs nested iteration, this paper describes techniques to execute such plans efficiently as well as means to cleanly implement these techniques. Taken together, these techniques can improve query performance by orders of magnitude, giving them obvious practical importance.
- KonferenzbeitragRealisierung eines adaptiven Replikationsmanagers mittels J2EE-Technologie(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Niemann, Heiko; Hasselbring, Wilhelm; Hülsmann, Michael; Theel, OliverDie Integration in heterogenen Systemlandschaften bedeutet häufig eine Kopplung zur Replikation von Daten lokaler, autonomer Systeme. Dabei soll einerseits Datenmanipulation unter Wahrung der Konsistenz erfolgen, andererseits sollen die beteiligten Systeme i.A. ihre Autonomie beibehalten. Dieser Konflikt der Anforderungen wird durch bekannte Replikationsverfahren nur begrenzt gelöst: Je nach Strategie wird ein Kompromiss zwischen Konsistenz und Autonomie eingegangen. Hier kann ein konfigurierbarer, adaptiver Replikationsmanager Abhilfe schaffen, der eine Kombination bildet aus synchroner Replikation, die eine hohe Konsistenz bei eingeschränkter Verfügbarkeit garantiert, und asynchroner Replikation, die bei eingeschränkter Konsistenz den Systemen eine größere Autonomie belässt. Die Konfiguration des Replikationsmanagers wird durch ein Regelsystem gesteuert, dass Faktoren wie Tageszeit oder Performanz berücksichtigt. Im vorliegenden Papier wird eine Realisierung des adaptiven Replikationsmanagers auf Basis der J2EE-Technologie vorgestellt. Sie bietet sich an, da hier z.B. Transaktions- und Nachrichtendienste genutzt werden können sowie Möglichkeiten zur technischen Anbindung der beteiligten Systeme zur Verfügung stehen.
- KonferenzbeitragMultidimensional mapping and indexing of XML(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Bauer, Michael G.; Ramsak, Frank; Bayer, RudolfWe propose a multidimensional approach to store XML data in relational database systems. In contrast to other efforts we suggest a solution to the problem using established database technology. We present a multidimensional mapping scheme for XML and also thoroughly study the impact of established and commercially available multidimensional index structures (compound B-Trees and UB-Trees) on the performance of the mapping scheme. In addition, we compare our multidimensional mapping to other known mapping schemes. While studying the performance we have identified projection and selection to be fundamental parts of a typical query on XML documents. Our measurements show that projection and selection are orthogonal and require special multidimensional index support to be processed efficiently.
- KonferenzbeitragAn ontology for domain-oriented semantic similarity search on XML data(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Theobald, AnjaQuery languages for XML such as XPath or XQuery support Boolean re- trieval where a query result is a (possibly restructured) subset of XML elements or entire documents that satisfy the search conditions of the query. Web search engines, on the other hand, are based on the ranked retrieval paradigm, but do not consider the additional information and rich annotations provided by the structure of XML documents and their element names. Furthermore, web search engines have very little "semantic" data and are thus unable to cope with ambiguous search terms. Ontological knowledge and appropriate index structures are necessary for semantic similarity search on XML data extracted from the web. In this paper we present a powerful ontology index which supports domain-specific semantic similarity search with a new measure for expressing the relevance of query results.