[gdal-dev] RFC 21: OGR SQL type cast and field name alias

[Tamas Szekeres]

I've updated

http://trac.osgeo.org/gdal/wiki/rfc21_ogrsqlcast

according to the changes mentioned below.

Best regards,

Tamas


2008/1/25, Tamas Szekeres <szekerest at gmail.com>:
> 2008/1/25, Frank Warmerdam <warmerdam at pobox.com>:
> >
> > How will you handle precision for floating point fields?
> >
>
> We could easily support that by using the SQL92 numeric type as:
> numeric [ ( field_length [, field_precision ] ) ]
>
> I'll update the RFC accordingly.
>
> > What about casting something to be an integer list, string list or floating
> > point list?  I don't mind it not being supported, but at least we should
> > be explicit on that point in the RFC.
> >
>
> I cannot support these easily since the corresponding conversion
> routines are missing in the OGR code. We have no such kind of types in
> SQL92 either so it could only be an OGR specific extension.
>
> >
> > In theory if we have a string formatted properly we should be
> > able to convert it to date/time format.  I see OGRFeature::SetField(int,const
> > char*) uses OGRParseDate() to set date/time fields from string input.  I
> > think this would be quite a useful cast.
> >
>
> Yes, I've possibly missed that. I'll add support converting to the
> datetimes as well. Here is my proposed data type definition that
> contains all of the changes mentioned above.
>
> <data type> ::= character [ ( field_length ) ]
>                 | float [ ( field_length ) ]
>                 | numeric [ ( field_length [, field_precision ] ) ]
>                 | integer
>                 | timestamp
>
> Because of these changes I'll have to add SWQ_DATETIME to the
> swq_field_type struct as well.
>
> Best regards,
>
> Tamas
>