Re: [gnome-db] Data Types translations.

[Bas Driessen <bas driessen xobas com>]

On Wed, 2006-08-30 at 15:36 +0200, Vivien Malerba wrote:
> On 8/30/06, Bas Driessen <bas driessen xobas com> wrote:
> [...]

> >
> >  Further to the discussion regarding the creation of the table. There is the
> > Path: /FIELDS_A/@COLUMN_TYPE. Here a complete type must be set. For
> > postgresql that is varchar(30) for instance. As mentioned before I would
> > like to see this part more provider independent. Perhaps we can reach some
> > sort of a compromise. First I tell you what I would like to see:
> >
> >  /FIELDS_A/@COLUMN_GTYPE
> >  /FIELDS_A/@COLUMN_SIZE
> >  /FIELDS_A/@COLUMN_SCALE
> >
> >  example values:
> >  GDA_TYPE_NUMERIC
> >  10
> >  2
> >
> >  This then will be translated by the postgresql provider for instance to
> > numeric(10,2).
> >
> >  To provide both options to the user, we can say that if
> > /FIELDS_A/@COLUMN_TYPE (the current situation), this overrules any
> > situation. If it is not set, the user should set
> >
> >  /FIELDS_A/@COLUMN_GTYPE
> >  /FIELDS_A/@COLUMN_SIZE  (if applicable)
> >  /FIELDS_A/@COLUMN_SCALE (if applicable)
> >
> >  Then for the various providers we can make this into something that works
> > for the data provider.
> >
>
> I agree on having the /FIELDS_A/@COLUMN_SIZE and
> /FIELDS_A/@COLUMN_SCALE as this makes things more provider
> independant.
>
> However I prefer to stay with a /FIELDS_A/@COLUMN_TYPE because it's
> closer to what a user can easily fill-in and it's easy for a
> programmer (using gda_server_provider_get_default_dbms_type()) to
> convert from a GType to a DBMS type. It also makes it possible to
> check and take actions when the provider doesn't support a particular
> GType before trying to execute the action.
>
> So I propose to have
> /FIELDS_A/@COLUMN_TYPE (required)
> /FIELDS_A/@COLUMN_SIZE (optional)
> /FIELDS_A/@COLUMN_SCALE (optional)
>
> Is it Ok for you? If so, can you make the modifications in the xml.in
> files and in the -ddl.c files for some or all of the providers?
Ok with me, but if you bring back everything to just COLUMN_TYPE (as opposed to also have COLUMN_GTYPE), how would you deal with the situation if a user sets the values as follows:

numeric(10,5) (rather than GDA_TYPE_NUMERIC)
10
5

In this case we should ignore the size and the scale, since numeric(10,5)(10,5) is rubbish of course. What is the best approach to deal with this you reckon?

I am more than happy to make the changes for the postgresql and mysql providers. Once I have everything stable/working again, I want/have to look into the Oracle provider as well. I need to bring that to the same level in libgda as mysql and postgresql (including recordset etc etc).

Bas.