[Python-es] consulta SQL

[Antonio Beamud Montero]

monoBOT escribió:
> Hola ... como puedo obtener la cantidad de columnas de una tabla?
>
> hice lo siguiente de modo rudimentario pero seguramente existe una 
> forma mucho mas directa ... alguna pista?
>
>
> orden = 'SELECT * FROM nombretabla WHERE id = 1' 
> cursor.execute(orden)
>  
> for objeto in cursor:
>     valor = len(objeto)-1
> ------------------------------------------------------------------------
>
>   

de http://www.python.org/dev/peps/pep-0249/:

 Cursor Objects should respond to the following methods and
    attributes:

        .description 
          
            This read-only attribute is a sequence of 7-item
            sequences.  

            Each of these sequences contains information describing
            one result column: 

              (name, 
               type_code, 
               display_size,
               internal_size, 
               precision, 
               scale, 
               null_ok)

            The first two items (name and type_code) are mandatory,
            the other five are optional and are set to None if no
            meaningful values can be provided.

            This attribute will be None for operations that
            do not return rows or if the cursor has not had an
            operation invoked via the .execute*() method yet.
            
            The type_code can be interpreted by comparing it to the


Es decir, si haces len(cursor.description) te dice el total de columnas.