[gdal-dev] SQLite dialect in OGRDataSource::ExecuteSQL
Pierluigi Guasqui
guasqui at actgate.com
Tue Feb 10 09:20:12 PST 2015
Even,
I set the environment variable CPL_DEBUG=ON and rerun my code. I found
the statement you mentioned:
SQLITE: OGR style SQLite DB found !
SQLITE: Spatialite not available. Implementing a few functions
OGR2SQLITE: sqlite3_declare_vtab(CREATE TABLE
"xrs_2010jan21_mf2_geometry_polygons"("et" FLOAT,"utc" VARCHAR(25), ...
but then it printed the following error:
ERROR 1: Cannot create virtual table for layer
'xrs_2010jan21_mf2_geometry_polygons' : CREATE VIRTUAL: invalid SQL
statement : CREATE TABLE "xrs_2010jan21_mf2_geometry_polygons"("et"
FLOAT,"utc" VARCHAR(25), ...
SQLITE: OGR style SQLite DB found !
ERROR 1: In ExecuteSQL(): sqlite3_prepare(select * from
xrs_2010jan21_mf2_geometry_polygons):
no such table: xrs_2010jan21_mf2_geometry_polygons
OGR: Unloading VirtualOGR module
Any idea why I am getting this error?
Thank you!
Pierluigi
Il 10/02/2015 13:42, Even Rouault ha scritto:
> Le mardi 10 février 2015 12:47:46, Pierluigi Guasqui a écrit :
>> Hi All!
>>
>> I am using the GDAL/OGR functions to query a shapefile. This is a sample
>> code I have been successfully running so far:
>>
>> OGRDataSource *poDS = OGRSFDriverRegistrar::Open(
>> "some/path/to/myshapefile.shp" );
>> OGRLayer *poLayer = poDS->ExecuteSQL( "select * from myshapefile",
>> NULL, NULL );
>> // ...
>> // fetching result features from "poLayer"
>> // ...
>> poDS->ReleaseResultSet( poLayer );
>> OGRDataSource::DestroyDataSource(poDS);
>>
>>
>> As you can see, I am currently using the OGR SQL dialect, as I am
>> passing NULL as the third parameter of the OGRDataSource::ExecuteSQL
>> function.
>>
>> Now I am trying to extend the SQL syntax to be able to use the OGR
>> SQLite dialect. I have successfully recompiled GDAL 1.11.1 with SQLite
>> support (version 3.8.5) but when I try to execute the same sample code
>> (passing "SQLITE" as the 3rd argument of the OGRDataSource::ExecuteSQL
>> function) I am getting the following error:
>>
>> In ExecuteSQL(): sqlite3_prepare(select * from myshapefile): no such
>> table: myshapefile
>>
>>
>> What is the table name that contains the shapefile features that I can
>> use in my SQL queries?
> Pierluigi,
>
> That should work... If you tried to configure GDAL several times, perhaps you
> should do a make clean.
>
> Could you try defining CPL_DEBUG=ON as environment variable and rerun your
> code. You should normally see a statement like the following one to create the
> SQLite virtual table that matches the shapefile layer :
>
> OGR2SQLITE: sqlite3_declare_vtab(CREATE TABLE "poly"("AREA" FLOAT,"EAS_ID"
> FLOAT,"PRFEDEA" VARCHAR(16),OGR_STYLE VARCHAR HIDDEN,"GEOMETRY"
> BLOB_POLYGON_2D_50000))
>
> Even
>
--
Pierluigi Guasqui
Software Engineer
Applied Coherent Technology Corporation (ACT)
www.actgate.com
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