Jeff Davis <pgsql@j-davis.com> writes:
> Updatable views provide a subset of the functionality of rules, but they
> do it automatically without much effort on the part of the DBA. That's
> great, but it won't replace rules.
Exactly --- but there is also a place for a low-effort, "do the right
thing" feature, which is pretty much what the SQL spec's concept of
updatable views is.
There's also some question about whether our current definition of rules
can even support a non-surprising implementation of an updatable view.
The issue of multiple evaluation of what might be volatile expressions
keeps coming up...
regards, tom lane