Use key_name instead of link_id
Some entities do not have a link_id, but all entities are guaranteed
to have a key_name (or an id).
from django.contrib.gis.db import models
from django.contrib.gis.tests.utils import mysql
# MySQL spatial indices can't handle NULL geometries.
null_flag = not mysql
class Country(models.Model):
name = models.CharField(max_length=30)
mpoly = models.MultiPolygonField() # SRID, by default, is 4326
objects = models.GeoManager()
def __unicode__(self): return self.name
class City(models.Model):
name = models.CharField(max_length=30)
point = models.PointField()
objects = models.GeoManager()
def __unicode__(self): return self.name
class State(models.Model):
name = models.CharField(max_length=30)
poly = models.PolygonField(null=null_flag) # Allowing NULL geometries here.
objects = models.GeoManager()
def __unicode__(self): return self.name
class Feature(models.Model):
name = models.CharField(max_length=20)
geom = models.GeometryField()
objects = models.GeoManager()
def __unicode__(self): return self.name
class MinusOneSRID(models.Model):
geom = models.PointField(srid=-1) # Minus one SRID.
objects = models.GeoManager()