This book constitutes the refereed proceedings of the 5th International Workshop on Databases in Networked Information Systems, DNIS 2007, held in Aizu-Wakamatsu, Japan in October 2007.

The 22 revised full papers presented together with 1 invited talk were carefully reviewed and selected for inclusion in the book. Focusing on data semantics and infrastructure for information management and interchange, the papers are organized in topical sections on geospatial decision-making, Web data management systems, infrastructure of networked information systems, and Web query and web mining systems.