You may me able to architect your application to do well-enough without Foreign Keys yet still require features that key-value stores do not provide, like SQL,

You may me able to architect your application to do well-enough without Foreign Keys yet still require features that key-value stores do not provide, like SQL, triggers, etc. In the specfic case of MySQL, while still horrifying (I agree with you! but it is one of the things you some times have to do at scale), you can create the Foreign Key constraints but then disable their verification and periodically look for violations, as described here: https://www.percona.com/blog/2011/11/18/eventual-consistency-in-mysql/ https://www.percona.com/blog/2011/11/18/eventual-consistency...