[gdal-dev] Update ShapeLayer

Mateusz Loskot mateusz at loskot.net
Sun Aug 10 08:35:24 EDT 2008

wow wrote:
> Hi,
>   To update shape files. i got two questions: 


For Shapefile updating issues, read this post:


>  1. How could i delete a field from a shapelayer?

You have to create new Shapefile based on attributes schema of the 
exisiting Shapefile but removing unwanted field.

If your shapefile stores any features, it's not possible to update its 

>  2. How to set a value to a specified field of all records?
 > Could i use SQL sentences like "set field_name='value'" on the
> datasource of shapelayer? 

You can do it programmatically with a script or C/C++ program.
OGR SQL [1] engine does not support SQL UPDATE/INSERT commands.

[1] http://gdal.org/ogr/ogr_sql.html

BTW, it's a good idea to scan the archives of this mailing list, where 
you will find a lot of discussion about updating Shapefile issues.

Best regards
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org

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