def get_select_format(self, fld):
        if self.connection.ops.select and hasattr(fld, 'geom_type'):
            # This allows operations to be done on fields in the SELECT,
            # overriding their values -- used by the Oracle and MySQL
            # spatial backends to get database values as WKT, and by the
            # `transform` method.
            sel_fmt = self.connection.ops.select

            # Because WKT doesn't contain spatial reference information,
            # the SRID is prefixed to the returned WKT to ensure that the
            # transformed geometries have an SRID different than that of the
            # field -- this is only used by `transform` for Oracle and
            # SpatiaLite backends.
            if self.query.transformed_srid and ( self.connection.ops.oracle or
                                                 self.connection.ops.spatialite ):
                sel_fmt = "'SRID=%d;'||%s" % (self.query.transformed_srid, sel_fmt)
        else:
            sel_fmt = '%s'
        return sel_fmt

    # Private API utilities, subject to change.
Returns the selection format string, depending on the requirements
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/contrib/gis/db/models/sql/compiler.py/GeoSQLCompiler.get_select_format