[gdal-dev] determine default SQL dialect

[Rahkonen Jukka]

Hi,

About INDIRECT_SQLITE dialect, it is documented in https://gdal.org/user/sql_sqlite_dialect.html
“If the datasource is SQLite database (GeoPackage, SpatiaLite) then SQLite dialect acts as native SQL dialect and Virtual Table Mechanism is not used. It is possible to force GDAL to use Virtual Tables even in this case by specifying “-dialect INDIRECT_SQLITE”. This should be used only when necessary, since going through the virtual table mechanism might affect performance.”
There is also an usage example for one special use case.

ES is documented in https://gdal.org/drivers/vector/elasticsearch.html.
MONGO_DB is documented in https://gdal.org/drivers/vector/mongodbv3.html.

-Jukka Rahkonen-


Lähettäjä: gdal-dev <gdal-dev-bounces at lists.osgeo.org> Puolesta Michael Sumner
Lähetetty: tiistai 2. elokuuta 2022 10.43
Vastaanottaja: gdal-dev <gdal-dev at lists.osgeo.org>
Aihe: [gdal-dev] determine default SQL dialect

Is it possible to determine the default SQL dialect  that will be used in the C++ API?

It seems like the logic to pivot on dialect choice is only available to drivers internally (they know if they have one), so a map of formats is enough - but I wonder if I'm missing an API hook.

Also, there appears to be dialect values DEBUG, INDIRECT_SQLITE, MONGO_DB, and ES in use but I gather they are for internal use (and so properly don't appear in the documentation).

Thanks very much, Mike


--
Michael Sumner
Software and Database Engineer
Australian Antarctic Division
Hobart, Australia
e-mail: mdsumner at gmail.com<mailto:mdsumner at gmail.com>
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