Noah,
> That's all true, but the system has no concept like "this cast validates the
> data, never changing it". We would first need to add metadata supporting such
> a concept. On the other hand, "create cast (json as text) without function;"
> leans only on concepts the system already knows.
>
Yeah, I'm thinking it might be worth coming up with a solution for that
specific case. As users upgrade from 9.0 and 9.1 to 9.3, they're going
to want to convert their text columns containing JSON to columns of the
JSON type, and are going to be surprised how painful that is.
Of course, if we get binary JSON in 9.4 (Oleg?), then a binary
conversion will be required, so maybe it's a moot point.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com