[yashap]

Curious to know what you mean by “no room.” As in the performance impact of FKs and extensive use of transactions was too high? In my experience (not insane scale, but around 1 million daily active users hitting DBs with TBs of data), the performance overhead of FKs and transactions is fairly minimal. Ad-hoc attempts to bring the same functionality almost always end up in a loss of referential integrity, corrupt/wrong data, lots of bug squashing, etc. Why waste all that dev time and introduce all those bugs when you can use battle tested approaches like FKs and transactions that can guarantee correctness, at only a small performance hit?