Ticket #12733: extent-patch.diff

django/contrib/gis/db/backends/mysql/operations.py

@@ -11 +11 @@
     select = 'AsText(%s)'
     from_wkb = 'GeomFromWKB'
     from_text = 'GeomFromText'
+    valid_aggregates = dict([(k, None) for k in ('Extent',)])
 
+    extent_sql = '''CONCAT_WS(',', MAX(X(%(field)s)), MAX(Y(%(field)s)), MIN(X(%(field)s)), MIN(Y(%(field)s)))''' 
+    extent = 'Extent'
+
     Adapter = WKTAdapter
 
     geometry_functions = {
@@ -31 +35 @@
 
     gis_terms = dict([(term, None) for term in geometry_functions.keys() + ['isnull']])
 
+    def convert_extent (self,box):
+        """
+        Returns a 4-tuple extent for the `Extent` aggregate, created by MIN/MAX
+        queries on the dataset
+        """
+        xmax, ymax, xmin, ymin =  map(float, box.split(','))
+        return (xmin, ymin, xmax, ymax)
+
+    def check_aggregate_support(self, aggregate):
+        """
+        Checks if the given aggregate name is supported (that is, if it's
+        in `self.valid_aggregates`).
+        """
+        agg_name = aggregate.__class__.__name__
+        return agg_name in self.valid_aggregates
+
     def geo_db_type(self, f):
         return f.geom_type
 
@@ -46 +66 @@
             placeholder = '%s(%%s)' % self.from_text
         return placeholder
 
+
+    def spatial_aggregate_sql(self, agg):
+        """
+        Returns the spatial aggregate SQL template and function for the
+        given Aggregate instance.
+        """
+        agg_name = agg.__class__.__name__
+        if not self.check_aggregate_support(agg):
+            raise NotImplementedError('%s spatial aggregate is not implmented for this backend.' % agg_name)
+        agg_name = agg_name.lower()
+        sql_template = getattr(self, agg_name + '_sql')
+        sql_function = getattr(self, agg_name)
+        return sql_template, sql_function
+
     def spatial_lookup_sql(self, lvalue, lookup_type, value, field, qn):
         alias, col, db_type = lvalue
 

django/contrib/gis/tests/relatedapp/tests.py

@@ -56 +56 @@
             qs = list(City.objects.filter(name=name).transform(srid, field_name='location__point'))
             check_pnt(GEOSGeometry(wkt, srid), qs[0].location.point)
 
-    @no_mysql
     @no_spatialite
     def test04a_related_extent_aggregate(self):
         "Testing the `extent` GeoQuerySet aggregates on related geographic models."