You have a version that is really really outdated. It is many years old. There have been 8 releases in the meanwhile. Relational was ported to use Python3 and Qt5 months ago. I don't know if this is the right section to post the bug. Sorry if I have made a mistake.
This seems to be the right section. The current homepage and source are at http://ltworf.github.io/relational/ https://github.com/ltworf/relational/archive/2.4.tar.gz
Salvo, you may want to fix this for the next release: $ desktop-file-validate relational.desktop relational.desktop: warning: boolean key "Terminal" in group "Desktop Entry" has value "0", which is deprecated: boolean values should be "false" or "true" relational.desktop: error: value "database;relational;algebra;educational;learn;educativo;relazionale;impara" for locale string list key "Keywords" in group "Desktop Entry" does not have a semicolon (';') as trailing character
Moreover, the Makefile `install` target lists a non-existent dependency `install_module_gui`, and is not parallel-safe (the dependent targets are run in parallel but they all use the same `build` directory).
The new version has been committed. Thanks for reporting. @sci-mathematics: are you interested in co-maintainership? sci-mathematics is a much better fit for this package than qt...
Thanks for the comments. I'll address them in the next release.
