OmniDB

OmniDB is designed to access PostgreSQL, MySQL, MariaDB, and Oracle in one interface, though it makes sure it provides full features for the PostgreSQL database.

OmniDB is developing quickly, with monthly feature releases, so I recommend that you check out the latest information at https://omnidb.org/.

OmniDB provides a very responsive interface and is designed with full security in mind. It can be used as a desktop application and it can also be served using a web server, to be accessed by the web browser of your choice.