/django/contrib/gis/db/models/sql/aggregates.py
Python | 61 lines | 39 code | 17 blank | 5 comment | 6 complexity | 604c437fbccfb9af1c3590ae3a60588e MD5 | raw file
Possible License(s): BSD-3-Clause
- from django.db.models.sql.aggregates import *
- from django.contrib.gis.db.models.fields import GeometryField
- from django.contrib.gis.db.models.sql.conversion import GeomField
- class GeoAggregate(Aggregate):
- # Default SQL template for spatial aggregates.
- sql_template = '%(function)s(%(field)s)'
- # Conversion class, if necessary.
- conversion_class = None
- # Flags for indicating the type of the aggregate.
- is_extent = False
- def __init__(self, col, source=None, is_summary=False, tolerance=0.05, **extra):
- super(GeoAggregate, self).__init__(col, source, is_summary, **extra)
- # Required by some Oracle aggregates.
- self.tolerance = tolerance
- # Can't use geographic aggregates on non-geometry fields.
- if not isinstance(self.source, GeometryField):
- raise ValueError('Geospatial aggregates only allowed on geometry fields.')
- def as_sql(self, qn, connection):
- "Return the aggregate, rendered as SQL."
- if connection.ops.oracle:
- self.extra['tolerance'] = self.tolerance
- if hasattr(self.col, 'as_sql'):
- field_name = self.col.as_sql(qn, connection)
- elif isinstance(self.col, (list, tuple)):
- field_name = '.'.join([qn(c) for c in self.col])
- else:
- field_name = self.col
- sql_template, sql_function = connection.ops.spatial_aggregate_sql(self)
- params = {
- 'function': sql_function,
- 'field': field_name
- }
- params.update(self.extra)
- return sql_template % params
- class Collect(GeoAggregate):
- pass
- class Extent(GeoAggregate):
- is_extent = '2D'
- class Extent3D(GeoAggregate):
- is_extent = '3D'
- class MakeLine(GeoAggregate):
- pass
- class Union(GeoAggregate):
- pass