Subject: Re: psycopg3 and adaptation choices
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From: Federico Di Gregorio <fog@dndg.it>
Organization: DNDG srl
Message-ID: <1546497c-ff41-9bd0-b4d7-931bd305caac@dndg.it>
Date: Mon, 9 Nov 2020 13:05:00 +0100
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On 09/11/20 13:00, Daniele Varrazzo wrote:
> On Mon, 9 Nov 2020 at 06:57, Federico Di Gregorio <fog@dndg.it> wrote:
[snip]
>> IMHO, oid is a bad idea
>> because it has a very specific semantic and the error messages generated
>> by PostgreSQL will be more confusing.
> 
> I'm not sure I understand this. At the moment, the oids are something
> that don't really surface to the end-users, who are not required to
> use them explicitly and shouldn't be seen in the error messages. For
> instance the query above might results in a call:
> 
>      >>> from psycopg3.oids import builtins
>      >>> builtins["numeric"].oid
>      1700
> 
>      >>> res = conn.pgconn.exec_params(b"select '[]'::jsonb -> $1",
> [b"1"], [1700])
>      >>> res.status
>      <ExecStatus.FATAL_ERROR: 7>
> 
>      >>> print(res.error_message.decode("utf8"))
>      ERROR:  operator does not exist: jsonb -> numeric
>      LINE 1: select '[]'::jsonb -> $1
>                                ^
>      HINT:  No operator matches the given name and argument types. You
> might need to add explicit type casts.
> 
> So the oid is only used internally, in the mapping python type ->
> exec_params() types array, the 1700 shouldn't surface anywhere.
> 
> Maybe I'm misunderstanding your concern: can you tell me better?

My fault. I misread and though you wanted to use OID as *the* type to 
pass to PostggreSQL for numbers.

federico