Re: Arrays of arrays

Merlin Moncure <mmoncure(at)gmail(dot)com> Thursday 07 April 2011 15:53:00
> On Thu, Apr 7, 2011 at 4:39 AM, rsmogura <rsmogura(at)softperience(dot)eu> wrote:
> > Hello,
> >
> > May I ask if PostgreSQL supports arrays of arrays directly or indirectly,
> > or if such support is planned? I'm interested about pseudo constructs
> > like: 1. Directly - (integer[4])[5] - this is equivalent to
> > multidimensional array, but may be differently represented on protocol
> > serialization (as array with array of elements).
> > 2. Indirectly - like create domain d as integer[6], d[11], or by any
> > other means.
> >
> > Currently, I think both of this, are unsupported and array should be only
> > base type. I ask about this, to create extend array support in JDBC.
>
> if you want to do serialization of complex structures through the
> protocol, your best bet currently is to use composites. for example,
> if you want to make array of arrays that are not all the same length
> (if they were the same length, why not use regular array?):
>
> create type t (i int[]);
> select array[row(array[1,2])::t, row(array[1,2,3,4])::t];
>
> merlin

No, I'm asking due to development of driver, just I don't want to expose some
functionality that may cause problems in future, when arrays of arrays will be
available, so it's quite important.

Just one more topic to discussion: should zero length arrays, like int[5][0]
[6], be available? Or error should be thrown?

Regards,
Radek.