With SchemaCrawler is it possible to generate a visual representation of the Database schema of OpenNMS. It is a often requested feature from people using OpenNMS especially when they need to get access to data which is not available through API. They provide also a docker image and maven plugins so it seems to be possible to integrate this as part of the developer documentation. A sample output for Horizon 20.0.1 is attached and also a docker-compose file which allows to generate the schema against the specific Horizon 20.0.1 version.