Database server: The database server collects the state of the resources that need to be monitored in time by communicating with the HTTP-CoAP proxy server, which in turn takes care of retrieving the required data from the proper source. The data stored in the database are accessible through traditional web programming technologies. The information can either be visualized in the form of a web site, or exported in any open data format using dynamic web programming languages. In the Padova Smart City network, the database server is realized within the WSN Gateway, which hence represents a plugand-play module that provides a transparent interface with the peripheral nodes.