Most database products ship with some test sample databases you can use for practice. We'll summaries here the most significant and free example databases from well-known relational database products. Each will be introduced with one or more model diagrams, and a list of tables, with total number of records and the estimated occupied size.
Connect to most popular database types to extract metadata. Generate flexible and dynamic database diagrams with our free Model Xtractor. Export them as Graphviz DOT files. And render them instantly on Graphviz online applications, by simply pasting the content of the exported files.