The choice by the KM3NeT Collaboration to use a relational data base for storage and bookkeeping of detector construction data, calibration data and management data is base d on the experience of the ANTARES Collaboration, but has a broader horizon. Currently, the core of the system is an Oracle Real Application Cluster installation hosted at the CCIN2P3 computing centre in Lyon, but a geographically distribu ted database network is foreseen. Database access is provided by an Application Web server that not only provides a graphical user interface, but also channels HTTP requests to SQL to optimally retrieve or insert data, potentially establ ishing a bridge towards Cloud or Grid computing models.