In most web mashup applications, the content is generated using either web feeds or an application programming interface (API) based on web services. Both approaches have limitations. Data models provided by web feeds are not powerful enough to permit complex data structures to be transmitted. APIs based on web services are usually different for each web application, and thus different implementations of the APIs are required for each web service that a web mashup application uses. We propose a database-driven approach to web mashups that supports integration at the database level and enables mashup developers to work with a uniform abstract model and have direct access to powerful features of database systems. We describe how we have implemented this approach based on an object-oriented database system with a rich object model and a generic proxy mechanism for data integration and synchronisation.