Re: Howto explicit cast types for PG-functions?

Il giorno dom, 24/05/2009 alle 14.57 -0600, Christopher D. Kyle ha
scritto: 
> Hi Martin,
> 
> I'm new to psycopg but I think you are on the right track using the 
> pyformat for assigning your variables in the execute statement. As I see 
> it , you simply need to list your formatting in the correspondingly 
> C-style.
> 
> %(var)s  - means format as a valid PostgreSQL formatted string (e.i.: 
> 'single quote string' )
> %(var)f  - means format as a valid PostgreSQL formatted float (e.i.: 3.14 )
> %(var)d  - means format as a valid PostgreSQL formatted integer (e.i.: 42)

No no no. Never do that. The format should always be "s" because it is a
marker, not a real format. Starting from 2.1 psycopg will throw a
warning on wrong marker usage.

The right way to do what Martin wants is to create a custom type adapter
(maybe overwriting the default one for integers). See the examples/
directory for example of both adapters (Python->PostgreSQL) and
typecasters (PostgreSQL->Python).

federico

-- 
Federico Di Gregorio                         http://people.initd.org/fog
Debian GNU/Linux Developer                                [email protected]
INIT.D Developer                                           fog-NGVKUo/i/[email protected]
 Credo fermamente che da qualche parte, in una scatola ci sia un gatto
  che non è vivo ne morto. Credo anche che se i fisici non si sbrigano
  a dargli una scatoletta, ben presto sarà solo morto.
                              -- adattato da una frase di Sam Black Crow

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