Discovering common databases on Linux

Most operating systems have one or two really popular, key database products associated with them. On Windows this is Microsoft SQL Server, for example. Linux is very different in this regard. Not only is one singular database product not closely ideologically associated with the operating system, but there is typically a plethora of database options available already included in nearly every Linux distribution. This makes it so much more challenging to be prepared to be a Linux system administrator because the expectation that you are knowledgeable of and ready to manage any number of various database products exists. Your theoretical Windows system administrator counterpart would, culturally, need only have knowledge of one very predictable product to claim base knowledge of the entire field. Many databases can run on Windows, but anything other than MS SQL Server is considered an oddity and specialized knowledge. There would never be an expectation...