[GRASS5] SQL support/DB backends

Hi Daniel, all

I have polished the examples (CSS) of
lib/db/sqlp/description.html
and was thinking about the limitations stated there.

Am I wrong that the limitations only apply to the
DBF driver? Once I use Postgresql etc, shouldn't I
get full SQL support such as provided by the DB backend?

If so, we should modify above page. If not so, we
should also clarify it :slight_smile:

Markus

On 11/15/2005 02:45 PM, Markus Neteler wrote:

Hi Daniel, all

I have polished the examples (CSS) of
lib/db/sqlp/description.html
and was thinking about the limitations stated there.

Am I wrong that the limitations only apply to the
DBF driver? Once I use Postgresql etc, shouldn't I
get full SQL support such as provided by the DB backend?

Yes. If you use SQLite or Postgres you will get the full power of SQL to
the db.* commands, since they pass the SQL to the DB backend. Atleast I
was able to do all kinds of nice avg, stddev etc when I used SQLite.

If so, we should modify above page. If not so, we
should also clarify it :slight_smile:

So we should modify it.

--W

Yup, you are both right. The point is that the documentation is
supposed to be the grass sql parser documentation, which is currently
only used for DBF. AFAICT it was supposed to be also used for textfile
access, but there is no working txt driver now.

The docs could state that those are the minimum SQL constructs that
grass understands; anything fancier depends on the driver support.
Getting the phrasing right might be tricky...

Daniel.

On 11/15/05, Wolf Bergenheim <wolf+grass@bergenheim.net> wrote:

On 11/15/2005 02:45 PM, Markus Neteler wrote:
> Hi Daniel, all
>
> I have polished the examples (CSS) of
> lib/db/sqlp/description.html
> and was thinking about the limitations stated there.
>
> Am I wrong that the limitations only apply to the
> DBF driver? Once I use Postgresql etc, shouldn't I
> get full SQL support such as provided by the DB backend?
>

Yes. If you use SQLite or Postgres you will get the full power of SQL to
the db.* commands, since they pass the SQL to the DB backend. Atleast I
was able to do all kinds of nice avg, stddev etc when I used SQLite.

> If so, we should modify above page. If not so, we
> should also clarify it :slight_smile:

So we should modify it.

--W

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Daniel Calvelo wrote:

Yup, you are both right. The point is that the documentation is
supposed to be the grass sql parser documentation, which is currently
only used for DBF. AFAICT it was supposed to be also used for textfile
access, but there is no working txt driver now.

The docs could state that those are the minimum SQL constructs that
grass understands; anything fancier depends on the driver support.
Getting the phrasing right might be tricky...

Maybe a native speaker is needed here? Or someone, who approximates a
native speaker
well...

Markus