Re: Does Type Have = Operator?

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От
Jim Nasby
Тема
Re: Does Type Have = Operator?
Дата
в 15:10:47
Msg-id
2d0f10b8-bb4b-be5f-f6d0-19f16a4fdf93@BlueTreble.com
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Дерево обсуждения
Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? Tom Lane <tgl@sss.pgh.pa.us>
Re: Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? Euler Taveira <euler@timbira.com.br>
Re: Does Type Have = Operator? "David G. Johnston" <david.g.johnston@gmail.com>
Re: Does Type Have = Operator? Euler Taveira <euler@timbira.com.br>
Re: Does Type Have = Operator? Fabrízio de Royes Mello <fabriziomello@gmail.com>
Re: Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? Fabrízio de Royes Mello <fabriziomello@gmail.com>
Re: Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? Fabrízio de Royes Mello <fabriziomello@gmail.com>
Re: Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? Tom Lane <tgl@sss.pgh.pa.us>
Re: Does Type Have = Operator? Andrew Dunstan <andrew@dunslane.net>
Re: Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? Jim Nasby <Jim.Nasby@BlueTreble.com>
Re: Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? "David G. Johnston" <david.g.johnston@gmail.com>
Re: Does Type Have = Operator? Robert Haas <robertmhaas@gmail.com>
Re: Does Type Have = Operator? "David G. Johnston" <david.g.johnston@gmail.com>
Re: Does Type Have = Operator? Kevin Grittner <kgrittn@gmail.com>
Re: Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? Kevin Grittner <kgrittn@gmail.com>
Re: Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? Jim Nasby <Jim.Nasby@BlueTreble.com>
Re: Does Type Have = Operator? "David E. Wheeler" <david@justatheory.com>
Re: Does Type Have = Operator? Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
On 5/11/16 7:05 PM, David E. Wheeler wrote:
> On May 11, 2016, at 10:34 AM, Kevin Grittner  wrote:
>
>> I'm not clear enough on your intended usage to know whether these
>> operators are a good fit, but they are sitting there waiting to be
>> used if they do fit.
>
> Huh. I haven’t had any problems with IS DISTINCT FROM for rows, except for the situation in which a failure is thrown because the types vary, say between TEXT and CITEXT. That can drive the tester crazy, since it says something like:
>
>     Results differ beginning at row 3:
>         have: (44,Anna)
>         want: (44,Anna)
>
> But overall I think that’s okay; the tester really does want to make sure the type is correct.

Speaking specifically to is(), what I'd find most useful is if it at 
least hinted that there might be some type shenanigans going on, because 
I've run across something like your example more than once and it always 
takes a lot to finally figure out WTF is going on.

I think it'd also be useful to be able to specify an equality operator 
to is(), though that means not using IS DISTINCT.

Something else to keep in mind here is that is() is defined as 
is(anyelement, anyelement, text), which means you've lost your original 
type information when you use it. I don't think you could actually do 
anything useful here because of that.
-- 
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
855-TREBLE2 (855-873-2532)   mobile: 512-569-9461


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