[GRASS5] 5.7: dbf driver and 'double' initialization

[Markus Neteler]

On Tue, Sep 07, 2004 at 10:02:41AM +0200, Radim Blazek wrote:
> 'NULL' as default is OK, I think. 'IS NULL' is not supported 
> by dbf driver. In this special case, why do you need to use 
> 'WHERE'? All values are 'NULL' so you can maybe just
> 'UPDATE dourokukan SET forward=50'?

For the simple example which I have sent the WHERE is not
required. But it was just a simple example to illustrate
the problem (it was working some time ago...).

Markus

PS: will try Glynn's patch later today
 

 
> On Tuesday 07 September 2004 04:55, Markus Neteler wrote:
> > There seems to be a problem with the initialization of
> > double (maybe also int) type in the DBF driver of 5.7:
> >
> > echo "ALTER TABLE dourokukan ADD COLUMN forward double" | db.execute
> > echo "ALTER TABLE dourokukan ADD COLUMN backward double" | db.execute
> > echo "ALTER TABLE dourokukan ADD COLUMN length double" | db.execute
> >
> > dbfdump dourokukan.dbf
> >         cat label      forward             backward              length
> >           1 s3m        (NULL)               (NULL)               (NULL)
> >           3 e3.0m      (NULL)               (NULL)               (NULL)
> >           5 e5.5m      (NULL)               (NULL)               (NULL)
> >          13 s13.0      (NULL)               (NULL)               (NULL)
> >          15 yes        (NULL)               (NULL)               (NULL)
> >
> > I assume that it should be set to zero (0).
> > At least I don't know how to access these (NULL) values in
> > a later SQL update :
> >
> > echo "UPDATE dourokukan SET forward=50 WHERE forward=0" | db.execute
> > echo "SELECT * FROM dourokukan" | db.select
> > cat|label|forward|backward|length
> > 1|s3m|||
> > 3|e3.0m|||
> > 5|e5.5m|||
> > 13|s13.0|||
> > 15|yes|||
> >
> > Any advice is welcome,
> >
> >  Markus
> >
> >
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> 
>