[GRASS-dev] implementing drop column into DBF driver

[Martin Landa]

Hi Markus,

the patch has been committed to CVS. It would be nice if more users test it...

Best regards, Martin

2007/2/2, Markus Neteler <neteler at itc.it>:
> Martin,
>
> nice, I have tested it successfully (DBF driver).
> Also written v.db.dropcol and tested that with DBF and PG
> driver.
>
> Once you changes are in CVS, I'll submit v.db.dropcol.
> Still it would be good to have more people testing the
> proposed patch.
>
> Thanks
> Markus
>
> On Fri, Feb 02, 2007 at 05:35:19PM +0100, Martin Landa wrote:
> > Hi,
> >
> > I have tried to solve this problem. I think in a very ugly way, but it
> > seems to work (see the attached patch).
> >
> > Regards, Martin
> >
> > 2006/12/4, Markus Neteler <neteler at itc.it>:
> > >Hi,
> > >
> > >I tried to implement drop column into DBF driver to get
> > >rid of columns like 'cat_' when re-importing an exported map:
> > >echo "ALTER TABLE mymap DROP COLUMN cat_" | db.execute
> > >
> > >Attached the changes to lib/db/sqlp/ and /db/drivers/dbf/
> > >
> > >The idea is to load the table internally in SQLP_DROP_COLUMN
> > >(such as SQLP_ADD_COLUMN does) but to jump over the column
> > >which we want to drop.
> > >So I took load_table() and made it load_table_selective(),
> > >most likely in an ugly way.
> > >
> > >While ugly, it could work but apparently I never reach
> > >SQLP_DROP_COLUMN. It bails out with
> > >
> > >...
> > >D3/3: sql: ALTER TABLE mymap DROP COLUMN cat_
> > >D3/3: SQL statement parsed successfully: ALTER TABLE mymap DROP COLUMN cat_
> > >...
> > >D3/3: add_column(): tab = 11, type = 3, name = edg_id, width = 20,
> > >decimals = 6
> > >D3/3: Doing SQL command <8> on DBF table... (see include/sqlp.h)
> > >dbmi: Protocol error
> > >D2/3: G__home home = /home/neteler
> > >ERROR: Error while executing: "ALTER TABLE mymap DROP COLUMN cat_
> > >       "
> > >
> > >I have no clue why. Help is welcome.
> > >
> > >Thanks,
> > >Markus
>
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-- 
Martin Landa <landa.martin at gmail.com> * http://gama.fsv.cvut.cz/~landa *