Re: [psycopg] Solving the SQL composition problem

On 1/2/17 10:21 AM, Daniele Varrazzo wrote:
>> execute('insert into %s values ($1)', [42], ['my table'])
>>
>> Obviously this would be backwards incompatible, but I think that's
>> manageable.
> mmm... what I think is that if these objects' replacement rules were
> different one could leave the %s and %(name)s placeholder untouched
> for the query params.
>
> A natural choice could be to use the str.format syntax for the query
> composition, or a subset of it. Hence my example could be:
>
> cur.execute(
>     sql.SQL("insert into {} values (%s,
> %s)").format(sql.Identifier('my_table')),
>     [10, 20])
>
> This would largely remove the need for double escaping.

What I'm suggesting is to let Postgres handle the replacement of normal
values, using the prepared statement syntax of $1, $2, etc[1], and only
do identifier replacement in python (using quote_ident). That means a
lot less time spent parsing, and opens the door for eventually doing
more efficient stuff over the wire, like using binary type formats.

1: https://www.postgresql.org/docs/current/static/sql-prepare.html
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Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
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