There are a lot of companies still using WebObjects. EOF is WebObjects' ORM layer which virtually eliminates the need to manually write SQL. Unfortunately WebObjects, and therefor EOF, were ported to Java years ago.
I know you are looking for an Objective-C (or now, Swift?) solution but for RDMSs like MySQL, Oracle or Postgresql, anything that will run them will be capable of running Java as well and WebObjects will run on any platform that supports Java 1.4 or later, including "Cloud" deployments on Amazon, Azure, etc.
Java WebObjects 5.4.3 is available as a free download from Apple. There is an active developer community that has picked up where Apple's development left off and even holds yearly developer conferences.
Bug fixes and new features are being added regularly to WebObjects via Project Wonder, an open-source set of frameworks built on top of WebObjects.
Apple itself does not offer support and has not released any new versions to the public since 2008, however you can see by the URLs used by many of Apple's services such as the App Store, iTunes Store, etc (...apple.com/cgi-bin/WebObjects/...), it's still alive and well inside Apple.