[gdal-dev] access attribute (non-spatial) data in .mdb with PGeo Driver

[Even Rouault]

Le lundi 14 novembre 2011 20:44:35, Eli Adam a écrit :
> Hi all,
> 
> On Windows, I'm trying to access non-spatial tables in an .mdb file.
> With --debug on I see that the absence of a 'GDB_GeomColumns' table is
> the problem.
> 
> >ogrinfo --debug on Surveys.mdb
> 
> PGeo: EstablishSession(DRIVER=Microsoft Access Driver
> (*.mdb);DBQ=Surveys.mdb) ODBC: SQLDriverConnect(DRIVER=Microsoft Access
> Driver (*.mdb);DBQ=Surveys.mdb) PGEO: SELECT on GDB_GeomColumns fails,
> perhaps not a personal geodatabase? [Microsoft][ODBC Microsoft Access
> Driver] The Microsoft Jet database engine cann ot find the input table or
> query 'GDB_GeomColumns'.  Make sure it exists and tha t its name is
> spelled correctly.
> ODBC: SQLDisconnect()
> 
> I noticed this fairly recent commit, which seems to indicate that this
> is the desired behavior, http://trac.osgeo.org/gdal/changeset/21550

I'm confused because if you get to the point of having the trace " PGEO: 
SELECT on GDB_GeomColumns fails, perhaps not a personal geodatabase?" it means 
that you got after the test of r21550 (which should have discared this mdb as 
having no GDB_GeomColumns table), so I highly suspect you are not using trunk 
version for this test.

r21550 only enforces what existed before : the PGeo driver can only handle 
PGeo MDBs. The new test was introduced specifically to avoid the PGeo driver to 
try opening a MDB that should be recognized by the Geomedia driver (new in 
trunk).

> 
> I was able to access the non-spatial attributes by making a
> 'GDB_GeomColumns' table and falsely populating it (and ignoring the
> missing 'GDB_SpatialRefs' table errors).
> 
> TableName	FieldName	ShapeType	ExtentLeft	ExtentBottom	ExtentRight	
ExtentTop
> 	IdxOriginX	IdxOriginY	IdxGridSize	SRID	HasZ	HasM
> Survey	Shape	4	7255394.59721669	241841.239197335	7396378.9177745	
524650.46
> 1230004	0	0	141508.958339791	1	0	0
> 
> >ogrinfo -so Surveys.mdb Survey
> 
> ERROR 1: 'SELECT srtext FROM GDB_SpatialRefs WHERE srid = 1' failed.
> [Microsoft][ODBC Microsoft Access Driver] The Microsoft Jet database engine
> cann ot find the input table or query 'GDB_SpatialRefs'.  Make sure it
> exists and tha t its name is spelled correctly.
> INFO: Open of `Surveys.mdb'
>       using driver `PGeo' successful.
> 
> Layer name: Survey
> Geometry: Unknown (any)
> Feature Count: 20790
> Extent: (7255394.597217, 241841.239197) - (7396378.917775, 524650.461230)
> Layer SRS WKT:
> (unknown)
> Geometry Column = Shape
> DocumentName: String (25.0)
> SurveyDate: DateTime (19.0)
> ...
> 
> 
> If the general case requires a 'GDB_GeomColumns' table, could no
> 'GDB_GeomColumns' table be made a driver config option?

Why not using the generic ODBC driver for that use case ?

> 
> I noticed that the new Access MDB driver,
> http://gdal.org/ogr/drv_mdb.html , does not require a GDB_GeomColumns
> table (tested on ubuntu 10.04 and gdal trunk).

Yes, it can understand PGeo MDBs, Geomedia MDBs and generic MDBs.

> 
> 
> Thanks, Eli
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