SGER Collaborative Research: Support for Design of Evolving Information Systems

IIS-0339032

Principal Investigator

 Vassilis J. Tsotras
Department of Computer Science and Engineering
University of California, Riverside
Riverside, CA 92521
Phone: (909) 787-2888
Fax: (909) 787-4643
Email: tsotras@cs.ucr.edu
URL : http://www.cs.ucr.edu/~tsotras


Collaborators

 This is collaborative research with project IIS-0339259, PI: C. Zaniolo

Keywords

Evolving systems Design, Change management, Versioning.

Project Summary

 A perennial problem in designing information systems (IS) is enabling them to cope with continuous evolution. This problem manifests itself in many settings, including software management, configuration management and web-page evolution. The objective of this project is to extend database technology to better support the design and development of information systems that gracefully adapt to changes. Therefore, database systems must be extended with the ability to (i) manage and query efficiently temporal/historical information, (ii) support version control for data sets, and software artifacts, and (iii) reduce the problem of configuration management to that of temporal querying and version retrieval on the IS metadata. The solution approach proposed exploits the fact that most IS are now being designed (or re-designed) with a web-centered (typically XML-based) focus, and XML ability to unify data and metadata and support powerful query languages. The evolution of information systems---their data, metadata, and software artifacts--- is thus unified and modelled by time-stamped XML documents. These findings pave the way to designing information systems for evolution and maintainability.

Publications and Products

 This is a new project and there are no publications to report yet.

Project Impact

 This research project will develop and demonstrate new techniques for enabling information systems to cope with changes in the logical structure of data and metadata. This is a novel and timely approach that has the potential for a unified solution to information systems evolution. Because of the key role played by information systems in modern world, a broad range scientific, educational, and economic activities will benefit from these advances.

Goals, Objectives and Targeted Activities

Our plan calls for a major experiment to be conducted during this year to validate and improve our combined XML/DB approach to information system design for evolution. A real life evolving IS (a job placement application), where  there are frequent changes the structure of the underlying database and applications, will be used for our design experiment. The objective is to demonstrate the design of an information system that supports:

  • XML views and queries that survive changes in the underlying database schema and can access the whole database history without conversion,
  • management of multiple versions of evolving software artifacts, and other semistructured documents
  • integration of (i) and (ii) and efficient support through extensions of DBMS technology

We expect that difficult technical challenges will be encountered and brought into focus by this project. These include, support for branching versions of database and documents, support for complex queries, such as path expression queries, and many others that will emerge in the course of this exploratory project.

Area Background

 Information Systems (IS) have a long life cycle, during which they experience significant evolution in the structure and content of their databases, and major costs for data conversion and program migration [F03]. Unfortunately, current Data Base Management Systems (DBMSs) do not make it easy to design IS that gracefully cope with evolution [R96]. This situation calls for a new generation of database systems and tools whereby: (i) past information can be efficiently preserved and retrieved through historical queries, (ii) queries gracefully survive changes in the database schema, and (iii) multiple versions of documents and software can be managed efficiently by the DBMS (in support for historical queries and configuration management tools). These objectives require major advances in DBMS technology and architecture. In fact, current DBMSs are ineffective with evolving IS. For example, they do not support the preservation and the querying of past information, while schema changes generate major costs for data conversion and application migration. Moreover, traditional DBMS have been designed to support formatted information, rather than the variety of semistructured documents and software artifacts that are, in fact, needed for software configuration management. In particular, version management for stored data and documents is not yet supported in DBMSs. While these problems are very difficult to solve in traditional DBMSs, the database field is progressing fast because of the great pull of web applications. Thus, DBMSs are moving to provide content management, and publication of database content via XML. This trend provides exciting opportunities for novel database architectures and software tools to support the design IS for evolution. For instance, we have recently investigated how to represent historical information using XML and support historical queries using XQuery [WZ02, WZ03b]. Some schema information and schema changes are also represented naturally in the XML view of the underlying database. Thus, some queries on schema changes are also supported [WZ03a]. Furthermore we have also investigated efficient management of multiversion documents using XML, providing solutions that have desirable properties at both the logical and physical levels [CTZ01, CTZ02a, CTZ02b]. Related work in managing versions on semistructured and/or XML data appears in [CG98, CAW99, BKT02, MAC01]. Indexing issues related to managing versions in temporal databases appear in [LST95, JSL00].

Area References

 [F03] P. Freeman, ''Science of Design,'' NSF white paper, April 2, 2003.


[R96] J.F. Roddick, "A model for schema versioning in temporal database systems", In Proc. 19th. ACSC Conf., pages 446--452, 1996.

[WZ02] F. Wang and C. Zaniolo, "Preserving and querying histories of xml-published relational databases", In Proceedings of the Second International Workshop on Evolution and Change in Data Management (ECDM '02), Tampere, Finland, October 2002.

[WZ03a] F. Wang and C. Zaniolo, "Representing and querying the evolution of databases and their schemas in XML", In Workshop on Web Engineering, SEKE, San Francisco, USA, 2003.

[WZ03b] F. Wang and C. Zaniolo, "Temporal queries in XML document archives and web warehouses", In TIME-ICTL 2003, Cairns, Australia, 2003.

[CG98] S. Chawathe, H. Garcia-Molina, "Representing and Querying changes in semistructured data'', In Proc. of ICDE, pp. 4-13, 1998.

[CTZ01] S-Y. Chien, V.J. Tsotras and C. Zaniolo, "Efficient Management of Multiversion Documents by Object Referencing'', In Proc. VLDB'01, Roma, Italy, Sept. 2001.

[CTZ02a] S-Y. Chien, V.J. Tsotras and C. Zaniolo, "Efficient Schemes for Managing Multiversion XML Documents'', VLDB Journal, Vol. 11, No.4, pp 332-353, 2002.

[CTZ02b] S.-Y. Chien, V.J. Tsotras, C. Zaniolo and D. Zhang, "Efficient Complex Query Support for Multiversion XML Documents'', In Proc. EDBT, Prague, Czech Republic, March 2002.

[CAW99] S. Chawathe, S. Abiteboul and J. Widom, "Managing Historical Semistructured Data'', TAPOS, 5(3):143-162, 1999.

[BKT02] P. Buneman, S. Khanna, K. Tajima and W.C. Tan, "Archiving Scientific Data'', Proc. of ACM SIGMOD, 2002.

[MAC01] A. Marian, S. Abiteboul, G. Cobena and L. Mignet, "Change-centric management of versions in an XML warehouse'', In Proc. VLDB, Rome, Italy, Sep. 2001.

[LST95] G. M. Landau, J. P. Schmidt and V. J. Tsotras, "Historical Queries Along Multiple Lines of Time Evolution'', VLDB Journal, Vol.4, No.4, pp. 703-726, 1995.

[JSL00] L. Jiang, B. Salzberg, D. B. Lomet and M.B. García, "The BT-tree: A Branched and Temporal Access Method'', In Proc. VLDB, 2000.

Project Websites

UCLA: http://wis.cs.ucla.edu/nsf-projects/science-of-design
UCR: http://www.cs.ucr.edu/~tsotras/design.html