Transaktionsorientierte Verwaltung und Suche von Dokumenten in einer Mehrprozessordatenbankumgebung

Traditional database Systems provide efficient transaction oriented processing of structured data. However, usually, processing of textual data in a database system has either no or only limited support. For example, while it may be possible to build index structures over textual data, in practice, the resulting bottlenecks make this impracticable. The reason for these bottlenecks are pseudo conflicts arising from traditional protocols for concurrency control, such as two-phase locking, which were designed to prevent conflict between transactions rather than within transactions. In the first part of this thesis, we discuss these problems of combining efficient textual processing with traditional database Systems in detail. Existing research proposals for advanced transaction modeis, such as multi-level transactions, provide a theoretical basis for reducing the level of conflicts in a database System. The potential for adopting such protocols to solve the problem of online Updates of indexed textual data has previously been validated, but only in a research environment. This has been done either by building new prototype database Systems or by extending existing client-server database Systems with a preprocessor for textual data. However, over the last few years, there has been a shift in database technology: In the past, applications were mostly based on traditional clientserver technology. Today, applications are often based on middleware products. Especially in the area of online transaction processing, we have noticed an increasing number of applications built using transaction processing monitors (TP monitors). In a System based on TP monitors, users do not directly interact with the database System using, for example, SQL. Instead, they interface the database System using so-called "services". In the context of textual data, typical Services are the insertion of a textual document including the Updates of the textual index structures or the search for all documents containing certain keywords. Of course, TP monitors provide füll transactional support. In particular, it is possible to combine a number of service calls to a Single transaction. If we compare the concepts of multi-level database Systems, in particular a two level System, with TP monitors, we find that these concepts are very similar: In a two level database System, a user transaction consists of the execution of a number of higher level Operations, each of which is coded using lower level Operations. In a TP monitor environment, a user transaction is made up of a number of Service calls. Each of these Services consist of a number of calls to the underlying database System. Therefore, one could say that the higher level Operations of a two level database System are very similar to the Services of a TP monitor and lower level Operations are similar to the calls of the database System. In the second part of this thesis, we show how the similarity of multi-level database Systems and TP monitors can be exploited in order to build a fully operational multi-level database System: Based on commercial relational database Systems (Oracle and Sybase) as well as a commercial TP monitor (Tuxedo), the TP monitor is extended with a generic higher-level transaction manager. The resulting transaction manager provides support for the correct execution of two-