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from django.contrib.gis.gdal import OGRGeomType
from django.db.backends.sqlite3.introspection import DatabaseIntrospection, FlexibleFieldLookupDict
class GeoFlexibleFieldLookupDict(FlexibleFieldLookupDict):
"""
Sublcass that includes updates the `base_data_types_reverse` dict
for geometry field types.
"""
base_data_types_reverse = FlexibleFieldLookupDict.base_data_types_reverse.copy()
base_data_types_reverse.update(
{'point' : 'GeometryField',
'linestring' : 'GeometryField',
'polygon' : 'GeometryField',
'multipoint' : 'GeometryField',
'multilinestring' : 'GeometryField',
'multipolygon' : 'GeometryField',
'geometrycollection' : 'GeometryField',
})
class SpatiaLiteIntrospection(DatabaseIntrospection):
data_types_reverse = GeoFlexibleFieldLookupDict()
def get_geometry_type(self, table_name, geo_col):
cursor = self.connection.cursor()
try:
# Querying the `geometry_columns` table to get additional metadata.
cursor.execute('SELECT "coord_dimension", "srid", "type" '
'FROM "geometry_columns" '
'WHERE "f_table_name"=%s AND "f_geometry_column"=%s',
(table_name, geo_col))
row = cursor.fetchone()
if not row:
raise Exception('Could not find a geometry column for "%s"."%s"' %
(table_name, geo_col))
# OGRGeomType does not require GDAL and makes it easy to convert
# from OGC geom type name to Django field.
field_type = OGRGeomType(row[2]).django
# Getting any GeometryField keyword arguments that are not the default.
dim = row[0]
srid = row[1]
field_params = {}
if srid != 4326:
field_params['srid'] = srid
if isinstance(dim, basestring) and 'Z' in dim:
field_params['dim'] = 3
finally:
cursor.close()
return field_type, field_params
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