[GRASSLIST:9378] Re: Some question about db...

[Maciek Sieczka]

On czw, 2005-12-08 at 12:28 +0000, Luca Casagrande wrote:
> Hi guys...
> I am moving the first step on db operation: following the info on this page, 
> http://grass.itc.it/grass61/manuals/html61_user/sql.html , I notice that the 
> command GROUP BY is not supported by DBF driver; I need to use DBMS to have 
> full support for SQL.
> Running db.drivers I got only DBF and OGR as output... how can I enable DBMS ?

I don't know if Grass packages provided by different distros and the
binaries at grass.itc.it are built with other DBMS support than for DBF
only.

In case you build from source, do ./configure --help first to read how
to enable different DBMS support. See the INSTALL file too. As to
postgres, from my experience once you have postgres devel packages in
your system Grass will automatically pick them and build with postgres
(at least this is the case for me in Mandriva 2005 and Ubuntu Hoary when
talking of Grass 6.1). If it doesn't, use different ./configure switches
to help it.

Recently there's been added support for sqlite in 6.1, which is not a
database server like posgres, much easier to use I think and quite
powefull, faster and more powerfull than DBF for sure. Might be an
interesting alternative to postgres, but I don't know how stable it is
now. Several days ago I experienced a complete system freeze using
v.out.ogr to export only 173863 lines with attributes stored in an
sqlite database in Grass. Maybe it is fixed now - Anybody knows? See
[GRASSLIST:9183] sqlite driver - remarks and questions, 22.11.2005.

Maciek


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