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

From Robert Haas
Subject Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL)
Date
Msg-id CA+Tgmoaj9YoGHv=8DT=JqFE3O0DZYzGJfsTYGeRaXdyu+e548g@mail.gmail.com
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In response to Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL)  (Brendan Jurd <direvus@gmail.com>)
Responses Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL)
List pgsql-hackers
On Tue, Mar 26, 2013 at 4:39 PM, Brendan Jurd <direvus@gmail.com> wrote:
> On 27 March 2013 06:47, Robert Haas <robertmhaas@gmail.com> wrote:
>> On Tue, Mar 26, 2013 at 9:02 AM, Brendan Jurd <direvus@gmail.com> wrote:
>>> We can't sensibly test for whether an array is empty.  I'd call that a
>>> functional problem.
>>
>> Sure you can.  Equality comparisons work just fine.
>>
>> rhaas=# select '{}'::int4[] = '{}'::int4[];
>
> The good news is, if anybody out there is using that idiom to test for
> emptiness, they will not be disrupted by the change.

According to the discussion downthread, apparently they will, because
you're introducing an infinitude of empty arrays, not all of which
compare equal to '{}'::int4.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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