[GRASS-user] sqlite database connection problems

[Johannes Radinger]

-------- Original-Nachricht --------
> Datum: Tue, 17 May 2011 16:39:31 +0200
> Von: "Johannes Radinger" <JRadinger at gmx.at>
> An: Markus Neteler <neteler at osgeo.org>
> CC: grass-user at lists.osgeo.org
> Betreff: Re: [GRASS-user] sqlite database connection problems

> 
> -------- Original-Nachricht --------
> > Datum: Tue, 17 May 2011 15:50:51 +0200
> > Von: Markus Neteler <neteler at osgeo.org>
> > An: Johannes Radinger <JRadinger at gmx.at>
> > CC: GRASS user list <grass-user at lists.osgeo.org>
> > Betreff: Re: [GRASS-user] sqlite database connection problems
> 
> > On Tue, May 17, 2011 at 2:01 PM, Johannes Radinger <JRadinger at gmx.at>
> > wrote:
> > > Hello,
> > >
> > > I tried to delete a vector file but I got following error:
> > >
> > > g.remove vect=river_gen at Cele
> > > Removing vector <river_gen at Cele>
> > > DBMI-SQLite driver error:
> > > Unable to open database: unable to open database file
> > > Unable to open database </Users/Johannes
> > Radinger/Documents/GRASS-GIS/Cele_location/Cele/sqlite.db/> by driver
> <sqlite>
> > 
> > The trailing slash at sqlite.db/ should not be there.
> > 
> > ...
> > > So i tried to list the the database connection and tables of my
> database
> > and but there is that table existing:
> > >
> > > db.connect -p
> > > driver:sqlite
> > > database:$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite.db/
> > 
> > sqlite.db is a file, with / triling GRASS may think that this indicates
> a
> > directory.
> > 
> > You need to define the DB link properly. That is in the VAR
> > file in the mapset (ASCII file) as well as in the dbln file of the
> > vector map - you can easily fix that with a text editor.
> > Be sure to avoid the trailing slash in future for the SQLite
> > backend, see manual of the grass-sqlite driver.
> 
> Oh I didn't recognize the trailing slash. 
> 
> But there are still some problems/questions I've got with sqlite database.
> I created a totally new mapset (no sqlite database existing in the
> beginning) and then I tried following script:
> 
> 
> 
>     input_barriers = options['barriers']
> 
>     env = grass.gisenv()
> 
>     gisdbase = env['GISDBASE']
>     location = env['LOCATION_NAME']
>     mapset = env['MAPSET']
> 
>     grass.run_command("db.connect",
>                       driver = "sqlite",
>                       database =
> os.path.join(gisdbase,location,mapset,'sqlite.db'),
>                       flags = "c")
> 
> 
>     grass.run_command("v.in.ascii",
>                       flags = "n",
>                       overwrite = True,
>                       input=input_barriers,
>                       output="barriers",
>                       skip=1,
>                       columns="x DOUBLE, y DOUBLE, clearance DOUBLE")
> 
> Is there now a table in the sqlite database created or not? I don't think
> so (checked with the SQlite Manager), but if I try
> grass.run_command("v.db.addtable", map="barriers") it says there is already a table linked to it.
> Is there a link to the old default database although the sqlite database was
> set before?


It seems that I found the problem. It is the c flag in db.connect. The manual says "Check connection parameters, set if uninitialized, and exit" and uninitialized means probably totally uninitialized. So the connection isn't set to e.g sqlite if already a dbf connection exists when the c-flag is set.

/johannes

> 
> /Johannes
> 
> 
> 
> 
> > 
> > Markus
> 
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