Re: multiset patch review

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Fri, Feb 4, 2011 at 1:15 PM, Itagaki Takahiro
> <itagaki(dot)takahiro(at)gmail(dot)com> wrote:
>> Multisets. But I chose the same function name and syntax because
>> arrays *are* multisets by definition.
>
> In math class, maybe. But in programming, no. Multiset is a
> datatype. Array is a different datatype. There is no reason why we
> need to clutter our parser with extra keywords to support a
> non-standard feature extension.

My understanding is that we will have to have those functions defined
and user visible, and that we benefit from function overloading which is
not in the standard. So there's no reason not to provide those function
for arrays already, then extend to full multiset support.

Given PostgreSQL overloading, yes, arrays are multisets as far as
defining those standard compliant APIs is concerned. AFAIUI.

Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support