166 research outputs found
Constraints for Semistructured Data and XML
Integrity constraints play a fundamental role in database design. We review initial work on the expression of integrity constraints for semistructured data and XML
Type-Based Detection of XML Query-Update Independence
This paper presents a novel static analysis technique to detect XML
query-update independence, in the presence of a schema. Rather than types, our
system infers chains of types. Each chain represents a path that can be
traversed on a valid document during query/update evaluation. The resulting
independence analysis is precise, although it raises a challenging issue:
recursive schemas may lead to infer infinitely many chains. A sound and
complete approximation technique ensuring a finite analysis in any case is
presented, together with an efficient implementation performing the chain-based
analysis in polynomial space and time.Comment: VLDB201
Logics for Unranked Trees: An Overview
Labeled unranked trees are used as a model of XML documents, and logical
languages for them have been studied actively over the past several years. Such
logics have different purposes: some are better suited for extracting data,
some for expressing navigational properties, and some make it easy to relate
complex properties of trees to the existence of tree automata for those
properties. Furthermore, logics differ significantly in their model-checking
properties, their automata models, and their behavior on ordered and unordered
trees. In this paper we present a survey of logics for unranked trees
Component communication and data adaptation
Predefined components often require adaption to interoperate,
especially an adaption of the data
they exchange. This paper
presents an XML-based approach to the data adaption problem.
It
covers serialization of objects to XML, their transformation
with XSLT, as well as deserialization,
i.e., parsing and
reconstruction of the transformed objects. We statically analyze
classes
to generate specific document types and allow static
preprocessing. Compared to normal interpreted
XML processing,
this approach eliminates introspection overhead, thus
accelerating the
components communication
A lightweight XML-based middleware architecture
Predefined components often require adaption to make them work
together including an adaption of the data exchanged. The
present paper describes an XML based approach to solve the
adoption of data. It includes the serialization of objets to
XML, the transformation with XSLT, and the parsing and
construction of the transformed objects. The pre-agreed document
types involved allow a pre-compilation of the processes.
Compared to standard interpreted XML processing, this approach
reduces the online adaptation processes and speeds up the
components\u27 communication
REVERSE ENGINEERING BASED APPROACH FOR TRANSFERRING LEGACY RELATIONAL DATABASES INTO XML
XML (extensible Markup Language) has emerged, and. is being gradually accepted as the standard for data interchange over the Internet. Since most data is currently stored in relational database systems, the problem of converting relational data into XML assumes special significance. Many researchers have already done some accomplishments in this direction. They mainly focus on finding XML schema (e.g., DTD, XML-Schema, and RELAX) that best describes a given relational database with a corresponding well-defined database catalog that contains all information about tables, keys and constraints. However, not all existing databases can provide the required catalog information. Therefore, these applications do not work well for legacy relational database systems that were developed following the logical relational database design methodology, without being based on any commercial DBMS, and hence do not provide well-defined metadata files describing the database structure and constraints. In this paper, we address this issue by first applying the reverse engineering approach described in [2] to extract the ER (Extended Entity Relationship) model from a legacy relational database, then convert the ER to XML Schema. The proposed approach is capable of reflecting the relational schema flexibility into XML schema by considering the mapping of binary and nary relationships. We have implemented a first prototype and the initial experimental results are very encouraging, demonstrating the applicability and effectiveness of the proposed approach
On Language Processors and Software Maintenance
This work investigates declarative transformation tools in the context of software maintenance. Besides maintenance of the language specification, evolution of a software language
requires the adaptation of the software written in that language as well as the adaptation of the software that transforms software written in the evolving language. This co-evolution is studied to derive automatic adaptations of artefacts from adaptations of the language specification.
Furthermore, AOP for Prolog is introduced to improve maintainability of language specifications and derived tools.Die Arbeit unterstützt deklarative Transformationswerkzeuge
im Kontext der Softwarewartung. Neben der Wartung der
Sprachbeschreibung erfordert die Evolution einer Sprache
sowohl die Anpassung der Software, die in dieser Sprache geschrieben ist als auch die Anpassung der Software, die diese Software transformiert. Diese Koevolution wird untersucht, um automatische Anpassungen
von Artefakten von Anpassungen der Sprachbeschreibungen abzuleiten. Weiterhin wird AOP für Prolog eingeführt, um die Wartbarkeit von Sprachbeschreibungen und den daraus abgeleiteten Werkzeugen zu erhöhen
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