[gdal-dev] sqlite dialect and MySQL spatial input

[Even Rouault]

Le mardi 01 octobre 2013 08:58:22, Jukka Rahkonen a écrit :
> Even Rouault <even.rouault <at> mines-paris.org> writes:
> > I've just pushed in trunk a change to make SQLITE dialect available to
> > all
> 
> OGR
> 
> > drivers that have a specialized ExecuteSQL() implementation.
> 
> Hi,
> 
> Is this a correct interpretation:
> 
> - The default SQL dialect is "OGR SQL", except for databases when the
> default is to use the native SQL dialect of the RDBMS
> - The default dialect can be overridden by the -dialect parameter, which
> can take values "OGR SQL" or "SQLITE" and after your change this works for
> all drivers in a similar way.

Yes. Just to crrect : the string is OGRSQL (no space)

> 
> If this is right I will have a look at the documentation and see if there
> is something to improve. At least I would make a little addition into
> http://www.gdal.org/ogr2ogr.html
> Now there reads
> 
> -dialect dialect:
>     SQL dialect. In some cases can be used to use (unoptimized) OGR SQL
> instead of the native SQL of an RDBMS by passing OGRSQL. Starting with GDAL
> 1.10, the "SQLITE" dialect can also be used with any datasource.
> 
> It would be good to give the alternatives and a hint about how to give OGR
> SQL so that the space character will not cause trouble as
> 
> -dialect dialect:
>     SQL dialect. Can take values "OGR SQL" or "SQLITE".

Adding quote would be indeed good to avoid the confusion with space/nospace. 
Want to give a crack at it ?

> 
> Should we do something also for the statement "Starting with GDAL 1.10, the
> "SQLITE" dialect can also be used with any datasource" which is totally
> true with databases only after your commit
> http://trac.osgeo.org/gdal/changeset/26506

Not sure how to render the dynamics of before and after r26506. I would 
perhaps just keep it as it is currently to avoid confusion. Using SQLITE 
dialect with a RDBMS driver is kind of unusual use case (which was the thing 
that was finxed with r26506).

> 
> -Jukka Rahkonen-
> 
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