There might be one or more geometry column names, or it might be an empty string.
vapour_geom_name(dsource, layer =0L, sql ="")
Arguments
dsource: data source name (path to file, connection string, URL)
layer: integer of layer to work with, defaults to the first (0) or the name of the layer
sql: if not empty this is executed against the data source (layer will be ignored)
Returns
character vector of geometry column name/s
Details
It might be "", or "geom", or "ogr_geometry" - the last is a default name given when SQL is executed by GDAL but there was no geometry name, and 'SELECT * ' or equivalent was used.
This feature is required by the DBI backend work in RGDALSQL, so that when SELECT * is used we can give a reasonable name to the geometry column which is obtained separately.