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Re: Change in datetime type casting

From: Adrian Klaver <adrian(dot)klaver(at)gmail(dot)com>
To: psycopg(at)postgresql(dot)org
Subject: Re: Change in datetime type casting
Date: 2012-06-28 14:11:38
Message-ID: 4FEC661A.8090102@gmail.com (view raw or flat)
Thread:
Lists: psycopg
On 06/28/2012 02:21 AM, Daniele Varrazzo wrote:
> On Thu, Jun 28, 2012 at 7:30 AM, Federico Di Gregorio <fog(at)dndg(dot)it> wrote:
>> On 28/06/12 01:19, Adrian Klaver wrote:
>
>>> Note the addition of the casts. This is causing problems when using the
>>> hstore adapter as hstore expects a plain string. Is there a way to get
>>> around this?
>>
>> The cast were introduced because PostgreSQL 9.x is much strictier about
>> function signatures than the 8.x series. Sometimes functions taking
>> parameters were not found because of the implicit text->other type cast.
>
> Hstore is a mapping from strings to strings, not a generic dictionary
> mapping. There's never been a promise to adapt generic python
> dictionary (mapping hashable -> anything) into it. Even if you ram a
> python date into a postgres hstore, reading it back you will get a
> string.

Which begs the question why does the adapter not do str(value) when 
creating the ARRAY?

>
> You can write a custom adapter to map the datetimes to strings without
> the cast and use them into hstore.

Bigger question:) Is it possible to turn adaption off for a 
connection/cursor?

>
> -- Daniele
>


-- 
Adrian Klaver
adrian(dot)klaver(at)gmail(dot)com



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Subject: Re: Change in datetime type casting
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Subject: Re: Change in datetime type casting

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