[Gdal-dev] PGeo and ODBC support in OGR

[Frank Warmerdam]

On 12/2/05, Tamas Szekeres <szekerest at gmail.com> wrote:
> Frank,
>
> After implementing such an enhancement in the ODBC driver I have
> experienced, that the random feature access (using GetFeature) have not been
> working without sustaining a fid column (It may be assigned to the Mapserver
> line as well).

Tamas,

The spatial query support (using xmin, ymin, xmax, ymax) will
no doubt have made it more important to actually select a column
to be the FID.  Otherwise the resultset changes each time the spatial
query is applied (or cleared) and the fids all become meaningless.

The ODBC_OGR_FID configuration option (via MapServer CONFIG
line or environment) can be used to pick the name of the column
to use for FIDs.   It defaults to OGR_FID.


>  Without using fid the feature had been returned from the
> entire result set with the same record number as the provided id.
>
> Does this change dissolve this problem.

The ODBC_OGR_FID should make it possible to avoid this problem.
I would add that Steve's planned "one pass query" support in mapserver
will also solve this problem in the mapserver context (I think) as
persistent FIDs are not longer so important.

Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent