Re: Add ZSON extension to /contrib/

Greetings,

* Tom Lane (tgl@sss.pgh.pa.us) wrote:
> Matthias van de Meent <boekewurm+postgres@gmail.com> writes:
> > I like the idea of the ZSON type, but I'm somewhat disappointed by its
> > current limitations:
>
> I've not read the code, so maybe this thought is completely off-point,
> but I wonder if anything could be learned from PostGIS.  AIUI they
> have developed the infrastructure needed to have auxiliary info
> (particularly, spatial reference data) attached to a geometry column,
> without duplicating it in every value of the column.  Seems like that
> is a close analog of what's needed here.

Err, not exactly the same- there aren't *that* many SRIDs and therefore
they can be stuffed into the typemod (my, probably wrong, recollection
was that I actually pushed Paul in that direction due to being
frustrated with CHECK constraints they had been using previously..).

Not something you could do with a dictionary as what's contempalted
here.  I do agree that each jsonb/zson/whatever column should really be
able to have its own dictionary though and maybe you could shove *which*
of those dictionaries a given column uses into the typemod for that
column...  In an ideal world, however, we wouldn't make a user have to
actually do that though and instead we'd just build our own magically
for them when they use jsonb.

Thanks,

Stephen