Antonio Polo Márquez

Managing branch versioning in versioned/temporal XML documents

Due to the linear nature of time, XML timestamped solutions for the management of XML versions have difficulty in supporting non-lineal versioning. Following up on our previous work, which dealt with a new technique for the management of non-lineal versions of XML graph documents, called versionstamp, we have gone a step forward by adding temporal information to each version included in the document. Not only does it allow us to query the vDocuments on a temporal and version level but also we can manage branch versioning in the temporal axis. Moreover, to check its functionality, we have compared our technique to a timestamped XML solution and a set of Web services has been developed. The easy management of multiple versioning, the large number of queries in different XML standard query languages and its implementation by using only XML technology, are some of the advantages of the proposed technique.

An XQuery-based version extension of an XML native database

The goal of this paper is to show our experience in the design of an extension to an XML native database in order to add in a native way version features. Due to the lineal nature of time, XML timestamped solutions for the management of XML versions have difficulty in supporting non-linear versioning, and their implementations are scarce and not very portable. From our technique described in [6, 7], which allows us to manage branch versioning, we have developed our versioning system focusing on its high portability and platform independence properties. To achieve this, our versioning system is based exclusively on XML technology. The system is composed by XQuery modules, so that this allows its use not only in an XQuery engine but also in an XQuery-support XML native database. To test it, the modules have been integrated in an eXist XML native database, an XML difference tool is used to observe the changes made between versions, and the eXist web interface has been extended to make the management of XML versions easier.

A web-based version editor for XML documents

The goal of this demonstration is to show a web-based editor for versioned XML documents. The user interface is an Ajax-based application characterized by its friendliness, its simplicity and intuitive edition of XML documents as well as their versions, thereby avoiding users the complexity of a versioning system. In order to store the XML documents an XML native database, which has been extended to support versioning features as it is shown in [3], is used.

A data model for versioned XML documents using XQuery

Due to the linear nature of time, XML timestamped solutions for the management of XML versions have difficulty in supporting non-lineal versioning, and their implementations are few and portableless. This paper proposes a version data model for XML documents developed using the branch version technique for XML documents shown in [9, 10]. We have built a system following this model based on XQuery modules, so that it ensures us a high portability and it allows its use not only in XQuery engine but also in XQuery-support XML native databases. In order to verify it, the modules have been integrated in the eXist XML native database, a difference tool has been used to obtain the changes made between versions, and the eXist Web interface has been extended to make easy the management of XML versions.

Multi-dimensional Declustering Methods for Parallel Database Systems

This paper describes and evaluates new methods for relation declustering in parallel databases. To process queries in parallel, relations are partitioned across multiple processors, typically by using the value of one single attribute. This kind of declustering has resulted in poor performance in the presence of data skew. Alternatively, the work contained herein proposes several strategies to decluster a relation through the use of multiple attributes. To demonstrate the validity of our approach, a thorough performance evaluation is done. The findings demonstrate the effectiveness of this kind of partitioning methods as opposed to traditional ones. In addition we analyze the performance of the different strategies relative to the speed-up and scale-up metrics.