django1/django/contrib/gis/db/models/sql/where.py

65 lines
2.9 KiB
Python

import datetime
from django.db.models.fields import Field
from django.db.models.sql.where import WhereNode
from django.contrib.gis.db.backend import get_geo_where_clause, SpatialBackend
class GeoAnnotation(object):
"""
The annotation used for GeometryFields; basically a placeholder
for metadata needed by the `get_geo_where_clause` of the spatial
backend.
"""
def __init__(self, field, value, where):
self.geodetic = field.geodetic
self.geom_type = field._geom
self.value = value
self.where = tuple(where)
class GeoWhereNode(WhereNode):
"""
Used to represent the SQL where-clause for spatial databases --
these are tied to the GeoQuery class that created it.
"""
def add(self, data, connector):
"""
This is overridden from the regular WhereNode to handle the
peculiarties of GeometryFields, because they need a special
annotation object that contains the spatial metadata from the
field to generate the spatial SQL.
"""
if not isinstance(data, (list, tuple)):
return super(WhereNode, self).add(data, connector)
alias, col, field, lookup_type, value = data
if not hasattr(field, "_geom"):
# Not a geographic field, so call `WhereNode.add`.
return super(GeoWhereNode, self).add(data, connector)
else:
# `GeometryField.get_db_prep_lookup` returns a where clause
# substitution array in addition to the parameters.
where, params = field.get_db_prep_lookup(lookup_type, value)
# The annotation will be a `GeoAnnotation` object that
# will contain the necessary geometry field metadata for
# the `get_geo_where_clause` to construct the appropriate
# spatial SQL when `make_atom` is called.
annotation = GeoAnnotation(field, value, where)
return super(WhereNode, self).add((alias, col, field.db_type(), lookup_type,
annotation, params), connector)
def make_atom(self, child, qn):
table_alias, name, db_type, lookup_type, value_annot, params = child
if isinstance(value_annot, GeoAnnotation):
if lookup_type in SpatialBackend.gis_terms:
# Getting the geographic where clause; substitution parameters
# will be populated in the GeoFieldSQL object returned by the
# GeometryField.
gwc = get_geo_where_clause(table_alias, name, lookup_type, value_annot)
return gwc % value_annot.where, params
else:
raise TypeError('Invalid lookup type: %r' % lookup_type)
else:
# If not a GeometryField, call the `make_atom` from the
# base class.
return super(GeoWhereNode, self).make_atom(child, qn)