Re: hstores in pl/python

2010/12/15 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>

> 2010/12/15 Dmitriy Igrishin <dmitigr(at)gmail(dot)com>:
> >
> >
> > 2010/12/15 Florian Pflug <fgp(at)phlo(dot)org>
> >>
> >> On Dec15, 2010, at 18:33 , Dmitriy Igrishin wrote:
> >> > 2010/12/15 Florian Pflug <fgp(at)phlo(dot)org>
> >> > On Dec15, 2010, at 16:18 , Dmitriy Igrishin wrote:
> >> > >> 2010/12/15 Florian Pflug <fgp(at)phlo(dot)org>
> >> > >> On Dec15, 2010, at 02:14 , James William Pye wrote:
> >> > >> > On Dec 13, 2010, at 6:16 PM, Tom Lane wrote:
> >> > >> >> how do you identify which type OID is really hstore?
> >> > >> >
> >> > >> > How about an identification field on pg_type?
> >> > >> >
> >> > >> > CREATE TYPE hstore ..., IDENTIFIER 'org.postgresql.hstore';
> >> > >> > -- Where the "identifier" is an arbitrary string.
> >> > >>
> >> > >> I've wanted something like this a few times when dealing
> >> > >> with custom types within a client. A future protocol version
> >> > >> might even transmit these identifiers instead a the type's OID,
> >> > >> thereby removing the dependency on OID from clients entirely.
> >> > >
> >> > > In some another tread I've proposed CREATE TYPE ... WITH OID...
> >> > Yeah, and I believe type identifiers are probably what you were
> >> > really looking for ;-)
> >> > Indeed, but why OID cannot serve as identifier in this case ? Why to
> >> > encode the code ? :-)
> >> Because there are only 2^32 OIDs, so if people start picking them at
> >> random, sooner or later there will be collisions.
> >
> > Yes, but range of PostgreSQL's OIDs can be reserved. One or even ten
> > millions, e.g. can be enough.
> >
> >>
> >> > Type identifiers would solve
> >> > this, by providing an easy and unambiguous way to find specific types.
> >> > Agree with 1st assertion but disagree with 2nd. If I understand
> >> > correctly,
> >> > "identifier" is a second name for type (object), but Java-styled,
> right
> >> > ?
> >> > It probably does solve the problem if there are will be convention
> that
> >> > types org.postgresql.* are reserved.
> >> Yeah, that'd be the idea. If everyone uses reversed DNS-style names, and
> >> everyone picks a name belonging to a DNS zone under his control, there
> >> cannot be any collisions. At least for java packages, this seems to work
> >> pretty nicely.
> >>
> >> > But why not reserve name of type
> >> > "hstore" and prevent the user to create type with this reserved name ?
> >> > All this tells me one thing - to avoid conflicts of naming of specific
> >> > types
> >> > it is necessary to make them built-in.
> >> None of these solutions scale well.
> >
> > Well, If there are will be identifiers for each type, e.g.
> > org.postgresql.integer, why
> > they need to be built-in ? For "historical reasons" ? :-)
> > Let them also be in contribs...
>
> some types are used in system tables, so without support of these
> types, then you can't to add a new types. It's a egg-chicken problem
>
So, the formal criterion to make the type built-in is "the type is must be
primitive" ?

>
> Pavel
>
> >>
> >> best regards,
> >> Florian Pflug
> >>
> >>
> >
> >
> >
> > --
> > // Dmitriy.
> >
> >
> >
>

--
// Dmitriy.