© Springer-Verlag Berlin Heidelberg 2006 Representing Versions in XML Documents Using

Abstract. The problem of managing versions in XML documents can be ap-proached through traditional adapted procedures, based on managing XML op-erations (deltas) or using timestamped markups to represent the validity of each versioned tag within the document. The first solution entails a high reconstruc-tion cost for any version different from the current one. Whereas the second so-lution, due to the linear nature of time, implies that these techniques do not to support branched versioning. In this work, the XML data model is extended for the representation of different versions of XML documents that consists of marking the tags with a versionstamp instead of using a timestamp. This tech-nique is based on two ideas: on the one hand storing the ancestral relations of the versions (version tree) produced a new version is generated and on the other hand the version validity of each versioned tag is defined based on this tree (versionstamp). The easy management of multiple versioning, the wide number of queries in XML standard query languages and its implementation only using XML technology, are some of the advantages of the proposed technique.