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From: Vladimir Ryabtsev <[email protected]>
To: Federico Di Gregorio <[email protected]>
Cc: [email protected]
Subject: Re: psycopg3 and adaptation choices
Date: Mon, 9 Nov 2020 17:06:13 -0800
Message-ID: <CAMqTPqkac5xa=+kwKLj8DEr9OdrkJpEzJj4Re8VvKP=JeTdZog@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
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> I wouldn't want to step away from the %s placeholder ...

Thanks for the elaboration, I agree with your argumentation.

> If there is interest we can think about how to make this querying layer
> more accessible (e.g. using a `cur.execute(PgQuery("select $1, $2"),
[...])`

It's always good if such customization is accessible. Having said that,
I can't think of a really good example that benefits from that rather than
from standard use, but basically the more possibilities the better.

> In psycopg3 I've made it slightly easier to use by letting
> `SQL.format()` to accept any Python object

Great, thanks!

May I ask you again about using 'unknown' for numbers? Could you recap
all the downsides of this approach?

Vladimir


On Mon, 9 Nov 2020 at 04:05, Federico Di Gregorio <[email protected]> wrote:

> On 09/11/20 13:00, Daniele Varrazzo wrote:
> > On Mon, 9 Nov 2020 at 06:57, Federico Di Gregorio <[email protected]> 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
>
>
>
>


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