Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL)

Brendan Jurd <direvus@gmail.com> writes:
> On 7 April 2013 01:43, Kevin Grittner <kgrittn@ymail.com> wrote:
>> Your interpretation matches mine all around.  It is unfortunate
>> that we have hijacked the standard's syntax for arrays to add a
>> matrix feature.

> It really is unfortunate.  I wonder if it was done in an attempt to
> mimic Oracle behaviour.

Hardly likely.  That code goes back to Berkeley days (PostQUEL) ---
there is clear ancestry from the array code in Postgres v4r2 released
June 1994.  It's more or less a coincidence that it matches the SQL spec
at all, and I'd be astonished if it matched Oracle particularly closely.

> On the specific issue of CARDINALITY, I guess we need to decide
> whether we are going to pretend that our array/matrix thing is
> actually nested.  I first argued that we should not.   But it occurred
> to me that if we do pretend, it would at least leave the door ajar if
> we want to do something to make our arrays more nest-like in future,
> without disrupting the behaviour of CARDINALITY.

This seems to be exactly the same uncertainty that we couldn't resolve
back in the 8.4 devel cycle, for exactly the same reasons.  I don't see
that the discussion has moved forward any :-(
        regards, tom lane