Apparently there are limitations that prohibit users from altering the data. Below is an extract from the manual. Limitations of the File Geodatabase API While the File Geodatabase API supports reading the schema and data of complex geodatabase types, the API does not honor geodatabase behavior on inserts, deletes or updates to the following dataset types: Annotation and Dimension feature classes Relationship Classes Networks (GN and ND) Topologies Terrains Representations Parcel Fabrics In most cases the API will prevent users from attempting to edit objects with complex behavior, but the onus is on the developer to understand what they should and should not edit through the API and avoid editing datasets that have geodatabase behavior. There is a method called Table::IsEditable which will provide developers with the ability to determine whether a dataset can be safely edited. Other limitations of the File Geodatabase API: Rasters (Raster Dataset, Raster Catalog, Mosaic Datasets and Raster Attributes) are not supported. Spatial queries with the File Geodatabase API will be limited to the envelope-intersects operator. Secure (licensed) Data is not supported.
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