Agreed, that would solve my aesthetic concerns and kinda solve OP's XY problem with JSON. But the performance of auto-created tables for every union member wou

Agreed, that would solve my aesthetic concerns and kinda solve OP's XY problem with JSON. But the performance of auto-created tables for every union member would kinda suck if you never take advantage of the relation and still pay the cost. You'd also have to auto-create indexes so that queries that read full objects is as fast (IOPS) as storing BLOBs. I was imagining a future database that takes this a step further and lets you define named parameterized queries next to your tables and chooses the best implementation of unions based on your queries. That's what I meant by "without thinking about it". We already do this for algorithms (query optimizer), and I'd love to see it work with data structures