78 lines
3.1 KiB
Python
78 lines
3.1 KiB
Python
from django.contrib.gis.gdal import OGRGeomType
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from django.db.backends.sqlite3.introspection import (
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DatabaseIntrospection, FlexibleFieldLookupDict,
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)
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class GeoFlexibleFieldLookupDict(FlexibleFieldLookupDict):
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"""
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Sublcass that includes updates the `base_data_types_reverse` dict
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for geometry field types.
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"""
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base_data_types_reverse = FlexibleFieldLookupDict.base_data_types_reverse.copy()
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base_data_types_reverse.update(
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{'point': 'GeometryField',
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'linestring': 'GeometryField',
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'polygon': 'GeometryField',
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'multipoint': 'GeometryField',
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'multilinestring': 'GeometryField',
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'multipolygon': 'GeometryField',
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'geometrycollection': 'GeometryField',
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})
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class SpatiaLiteIntrospection(DatabaseIntrospection):
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data_types_reverse = GeoFlexibleFieldLookupDict()
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def get_geometry_type(self, table_name, geo_col):
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cursor = self.connection.cursor()
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try:
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# Querying the `geometry_columns` table to get additional metadata.
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cursor.execute('SELECT coord_dimension, srid, geometry_type '
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'FROM geometry_columns '
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'WHERE f_table_name=%s AND f_geometry_column=%s',
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(table_name, geo_col))
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row = cursor.fetchone()
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if not row:
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raise Exception('Could not find a geometry column for "%s"."%s"' %
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(table_name, geo_col))
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# OGRGeomType does not require GDAL and makes it easy to convert
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# from OGC geom type name to Django field.
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ogr_type = row[2]
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if isinstance(ogr_type, int) and ogr_type > 1000:
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# SpatiaLite versions >= 4 use the new SFSQL 1.2 offsets
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# 1000 (Z), 2000 (M), and 3000 (ZM) to indicate the presence of
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# higher dimensional coordinates (M not yet supported by Django).
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ogr_type = ogr_type % 1000 + OGRGeomType.wkb25bit
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field_type = OGRGeomType(ogr_type).django
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# Getting any GeometryField keyword arguments that are not the default.
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dim = row[0]
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srid = row[1]
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field_params = {}
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if srid != 4326:
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field_params['srid'] = srid
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if (isinstance(dim, str) and 'Z' in dim) or dim == 3:
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field_params['dim'] = 3
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finally:
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cursor.close()
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return field_type, field_params
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def get_constraints(self, cursor, table_name):
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constraints = super().get_constraints(cursor, table_name)
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cursor.execute('SELECT f_geometry_column '
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'FROM geometry_columns '
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'WHERE f_table_name=%s AND spatial_index_enabled=1', (table_name,))
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for row in cursor.fetchall():
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constraints['%s__spatial__index' % row[0]] = {
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"columns": [row[0]],
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"primary_key": False,
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"unique": False,
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"foreign_key": None,
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"check": False,
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"index": True,
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}
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return constraints
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