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from django.contrib.gis.gdal import OGRGeomType
from django.db.backends.sqlite3.introspection import (
DatabaseIntrospection, FlexibleFieldLookupDict,
)
from django.utils import six
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, geometry_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.
ogr_type = row[2]
if isinstance(ogr_type, six.integer_types) and ogr_type > 1000:
# SpatiaLite versions >= 4 use the new SFSQL 1.2 offsets
# 1000 (Z), 2000 (M), and 3000 (ZM) to indicate the presence of
# higher dimensional coordinates (M not yet supported by Django).
ogr_type = ogr_type % 1000 + OGRGeomType.wkb25bit
field_type = OGRGeomType(ogr_type).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, six.string_types) and 'Z' in dim) or dim == 3:
field_params['dim'] = 3
finally:
cursor.close()
return field_type, field_params
def get_constraints(self, cursor, table_name):
constraints = super(SpatiaLiteIntrospection, self).get_constraints(cursor, table_name)
cursor.execute('SELECT f_geometry_column '
'FROM geometry_columns '
'WHERE f_table_name=%s AND spatial_index_enabled=1', (table_name,))
for row in cursor.fetchall():
constraints['%s__spatial__index' % row[0]] = {
"columns": [row[0]],
"primary_key": False,
"unique": False,
"foreign_key": None,
"check": False,
"index": True,
}
return constraints
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