  Database modeling is a key activity towards the fulfillment of storage
requirements. Despite the availability of several database modeling tools for
developers, these often come with associated costs, setup complexities,
usability challenges, or dependency on specific operating systems. In this
paper we present ONDA, a web-based tool developed at the University of Coimbra,
that allows the creation of Entity-Relationship diagrams, visualization of
physical models, and generation of SQL code for various database engines. ONDA
is freely available at https://onda.dei.uc.pt and was created with the
intention of supporting teaching activities at university-level database
courses. At the time of writing, the tool being used by more than three hundred
university students every academic year.
