Multilevel Versioning

“Straight” versioning systems for XML documents that produce a new version for every save, such as eXist DB's versioning extension, aren't as useful as they could be. They produce far too many versions, of which far too few are significant, and so each significant version is very hard to find or use. An old version, for example, cannot be easily located or reliably referenced. Adding check-out and check-in functionality would help alleviate some of the problems but not solve them. In this paper, I propose adding a multilevel, XML-based versioning abstraction on top of this “straight” versioning system, where any new versions are placed on different levels or stages, based on check-out and check-in operations that move the resources up or down in the versioning structure. The multilevel versioning is achieved using several different areas within the system, each of which in themselves is version handled using the system's “straight” versioning extension and where each save produces a system address to a specific (straight) version in that area. These addresses are kept track of and mapped to the multilevel versions in an XML-based version mapping file when a resource is checked in or out, as defined by the business rules for the abstraction.

From Temporal Databases to Ontology Versioning

The problem of versioning is present in several application areas, such as temporal databases, real-time computing and ontologies. This problem is generally defined as managing changes in a timely manner without loss of existing data. However, ontology versioning is more complicated than versioning in database because of the usage and content of ontology which incorporates semantic aspects. Consequently, ontology data models are much richer than those of database schemas. In this chapter, the authors are interested in developing an ontology versioning system to express, apply and implement changes on the ontology.