Re: Duplicate JSON Object Keys

On 03/08/2013 09:39 PM, Robert Haas wrote:
> On Thu, Mar 7, 2013 at 2:48 PM, David E. Wheeler <david@justatheory.com> wrote:
>> In the spirit of being liberal about what we accept but strict about what we store, it seems to me that JSON object
keyuniqueness should be enforced either by throwing an error on duplicate keys, or by flattening so that the latest key
wins(as happens in JavaScript). I realize that tracking keys will slow parsing down, and potentially make it more
memory-intensive,but such is the price for correctness.
 
> I'm with Andrew.  That's a rathole I emphatically don't want to go
> down.  I wrote this code originally, and I had the thought clearly in
> mind that I wanted to accept JSON that was syntactically well-formed,
> not JSON that met certain semantic constraints.

If it does not meet these "semantic" constraints, then it is not
really JSON - it is merely JSON-like.

this sounds very much like MySQLs decision to support timestamp
"0000-00-00 00:00" - syntactically correct, but semantically wrong.

> We could add
> functions like json_is_non_stupid(json) so that people can easily add
> a CHECK constraint that enforces this if they so desire.  But
> enforcing it categorically seems like a bad plan, especially since at
> this point it would require a compatibility break with previous
> releases
If we ever will support "real" spec-compliant JSON (maybe based
on recursive hstore ?) then there will be a compatibility break
anyway, so why not do it now.

Or do you seriously believe that somebody is using "PostgreSQL JSON"
to store these kind of "json documents"

Cheers
Hannu Krosing