[danielheath]

For sql specifically, “limit 2” is my default way to write “expect 1”; if it affects two rows, I know that I have screwed up, whereas “limit 1” can be wrong without my noticing.

[kristopolous]

That's not a terrible solution although expect sounds like a simple safety mechanism for feeble-minded people like me who do simple queries.

I actually know postgres people. I should probably ask them