extra(): Re-implemented. Now is polymorphic (nearly) without restrictions.
Added test cases + docs.fix_request_path_info
Bert Constantin
parent
6c8d28cbbc
commit
19adbdaf2c
40
DOCS.rst
40
DOCS.rst
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@ -262,14 +262,11 @@ About Queryset Methods
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to select relations in derived models
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(like ``ModelA.objects.select_related('ModelC___fieldxy')`` )
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* ``extra()`` by default works exactly like the original version,
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with the resulting queryset not being polymorphic. There is
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experimental support for a polymorphic extra() via the keyword
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argument ``polymorphic=True`` (only the ``where`` and
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``order_by`` and ``params`` arguments of extra() should be used then).
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The behaviour of extra() may change in the future, so it's best if you use
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``base_objects=ModelA.base_objects.extra(...)`` instead if you want to
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sure to get non-polymorphic behaviour.
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* ``extra()`` works as expected (returns polymorphic results) but
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currently has one restriction: The resulting objects are required to have
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a unique primary key within the result set - otherwise an error is thrown
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(this case could be made to work, however it may be mostly unneeded)..
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The keyword-argument "polymorphic" is no longer supported.
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+ ``get_real_instances(base_objects_list_or_queryset)`` allows you to turn a
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queryset or list of base model objects efficiently into the real objects.
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@ -488,19 +485,6 @@ Restrictions & Caveats
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for the methods of the polymorphic querysets. Please see above
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for ``translate_polymorphic_Q_object``.
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* Django 1.1 only - the names of polymorphic models must be unique
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in the whole project, even if they are in two different apps.
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This results from a restriction in the Django 1.1 "related_name"
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option (fixed in Django 1.2).
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+ Django 1.1 only - when ContentType is used in models, Django's
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seralisation or fixtures cannot be used (all polymorphic models
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use ContentType). This issue seems to be resolved for Django 1.2
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(changeset 11863: Fixed #7052, Added support for natural keys in serialization).
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+ http://code.djangoproject.com/ticket/7052
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+ http://stackoverflow.com/questions/853796/problems-with-contenttypes-when-loading-a-fixture-in-django
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* A reference (``ContentType``) to the real/leaf model is stored
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in the base model (the base model directly inheriting from
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PolymorphicModel). You need to be aware of this when using the
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@ -510,6 +494,20 @@ Restrictions & Caveats
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table needs to be corrected/copied too. This is of course generally
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the case for any models using Django's ContentType.
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+ Django 1.1 only - the names of polymorphic models must be unique
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in the whole project, even if they are in two different apps.
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This results from a restriction in the Django 1.1 "related_name"
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option (fixed in Django 1.2).
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* Django 1.1 only - when ContentType is used in models, Django's
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seralisation or fixtures cannot be used (all polymorphic models
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use ContentType). This issue seems to be resolved for Django 1.2
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(changeset 11863: Fixed #7052, Added support for natural keys in serialization).
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+ http://code.djangoproject.com/ticket/7052
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+ http://stackoverflow.com/questions/853796/problems-with-contenttypes-when-loading-a-fixture-in-django
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Project Status
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@ -30,11 +30,10 @@ class Command(NoArgsCommand):
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print Project.objects.all()
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print
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"""
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ModelA.objects.all().delete()
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a=ModelA.objects.create(field1='A1')
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b=ModelB.objects.create(field1='B1', field2='B2')
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c=ModelC.objects.create(field1='C1', field2='C2', field3='C3')
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print ModelA.objects.all()
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print
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"""
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@ -13,7 +13,7 @@ class ArtProject(Project):
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class ResearchProject(Project):
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supervisor = models.CharField(max_length=30)
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class ModelA(ShowFieldType, PolymorphicModel):
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class ModelA(ShowFieldTypeAndContent, PolymorphicModel):
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field1 = models.CharField(max_length=10)
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class ModelB(ModelA):
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field2 = models.CharField(max_length=10)
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@ -84,23 +84,11 @@ class PolymorphicQuerySet(QuerySet):
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self.polymorphic_disabled = True
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return super(PolymorphicQuerySet, self).aggregate(*args, **kwargs)
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def extra(self, *args, **kwargs):
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"""since django_polymorphic 'V1.0 beta2' extra() returns polymorphic results by default.
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Currently, for polymorphic queries, only the parameters 'where','order_by', 'params' are
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supported and an error is thrown if other parameters are given.
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For Django V1.1, extra() is not supported anymore (however it still works and returns
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non-polymorphic results as this is needed in django.db.models.base.save_base)."""
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polymorphic_by_default = not ( django_VERSION[0] <= 1 and django_VERSION[1] <= 1 )
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self.polymorphic_disabled = not kwargs.pop('polymorphic',polymorphic_by_default)
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if not self.polymorphic_disabled:
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for key in kwargs.keys():
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if key not in ['where','order_by', 'params']:
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assert False,("django_polymorphic: extras() does not yet support keyword argument '%s'."
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+ "You may use 'base_objects.extra()' instead - please see 'extra(' and 'get_real_instances' in DOCS.rst.") % (key,)
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return super(PolymorphicQuerySet, self).extra(*args, **kwargs)
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# Since django_polymorphic 'V1.0 beta2', extra() always returns polymorphic results.
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# The resulting objects are required to have a unique primary key within the result set
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# (otherwise an error is thrown).
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# The "polymorphic" keyword argument is not supported anymore.
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#def extra(self, *args, **kwargs):
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def get_real_instances(self, base_result_objects):
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"""
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@ -144,6 +132,11 @@ class PolymorphicQuerySet(QuerySet):
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self_model_content_type_id = ContentType.objects.get_for_model(self.model).pk
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for base_object in base_result_objects:
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ordered_id_list.append(base_object.pk)
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# check if id of the result object occeres more than once - this can happen e.g. with base_objects.extra(tables=...)
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assert not base_object.pk in base_result_objects_by_id, (
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"django_polymorphic: result objects do not have unique primary keys - model "+unicode(self.model) )
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base_result_objects_by_id[base_object.pk] = base_object
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# this object is not a derived object and already the real instance => store it right away
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@ -158,6 +151,7 @@ class PolymorphicQuerySet(QuerySet):
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# For each model in "idlist_per_model" request its objects (the real model)
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# from the db and store them in results[].
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# Then we copy the annotate fields from the base objects to the real objects.
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# Then we copy the extra() select fields from the base objects to the real objects.
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# TODO: defer(), only(): support for these would be around here
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for modelclass, idlist in idlist_per_model.items():
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qs = modelclass.base_objects.filter(id__in=idlist)
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@ -165,9 +159,15 @@ class PolymorphicQuerySet(QuerySet):
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for o in qs:
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if self.query.aggregates:
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for anno in self.query.aggregates.keys():
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attr = getattr(base_result_objects_by_id[o.pk], anno)
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setattr(o, anno, attr)
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for anno_field_name in self.query.aggregates.keys():
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attr = getattr(base_result_objects_by_id[o.pk], anno_field_name)
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setattr(o, anno_field_name, attr)
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if self.query.extra_select:
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for select_field_name in self.query.extra_select.keys():
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attr = getattr(base_result_objects_by_id[o.pk], select_field_name)
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setattr(o, select_field_name, attr)
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results[o.pk] = o
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# re-create correct order and return result list
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@ -175,10 +175,17 @@ class PolymorphicQuerySet(QuerySet):
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# set polymorphic_annotate_names in all objects (currently just used for debugging/printing)
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if self.query.aggregates:
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annotate_names=self.query.aggregates.keys() # get annotate fields list
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annotate_names=self.query.aggregates.keys() # get annotate field list
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for o in resultlist:
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o.polymorphic_annotate_names=annotate_names
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# set polymorphic_extra_select_names in all objects (currently just used for debugging/printing)
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if self.query.extra_select:
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extra_select_names=self.query.extra_select.keys() # get extra select field list
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for o in resultlist:
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o.polymorphic_extra_select_names=extra_select_names
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return resultlist
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def iterator(self):
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@ -40,16 +40,23 @@ class ShowFieldBase(object):
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else:
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out += ': "' + unicode(o) + '"'
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if hasattr(self,'polymorphic_annotate_names'):
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out += ' - Ann: '
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for an in self.polymorphic_annotate_names:
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if an != self.polymorphic_annotate_names[0]:
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def get_dynamic_fields(field_list, title):
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out = ' - '+title+': '
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for an in field_list:
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if an != field_list[0]:
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out += ', '
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out += an
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if self.polymorphic_showfield_type:
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out += ' (' + type(getattr(self, an)).__name__ + ')'
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if self.polymorphic_showfield_content:
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out += ': "' + unicode(getattr(self, an)) + '"'
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return out
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if hasattr(self,'polymorphic_annotate_names'):
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out+=get_dynamic_fields(self.polymorphic_annotate_names, 'Ann')
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if hasattr(self,'polymorphic_extra_select_names'):
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out+=get_dynamic_fields(self.polymorphic_extra_select_names, 'Extra')
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return out+'>'
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@ -33,6 +33,15 @@ class Model2C(Model2B):
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class Model2D(Model2C):
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field4 = models.CharField(max_length=10)
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class ModelExtraA(ShowFieldTypeAndContent, PolymorphicModel):
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field1 = models.CharField(max_length=10)
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class ModelExtraB(ModelExtraA):
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field2 = models.CharField(max_length=10)
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class ModelExtraC(ModelExtraB):
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field3 = models.CharField(max_length=10)
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class ModelExtraExternal(models.Model):
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topic = models.CharField(max_length=10)
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class ModelShow1(ShowFieldType,PolymorphicModel):
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field1 = models.CharField(max_length=10)
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m2m = models.ManyToManyField('self')
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@ -360,6 +369,21 @@ __test__ = {"doctest": """
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[ <Model2B: id 2, field1 (CharField), field2 (CharField)>,
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<Model2C: id 3, field1 (CharField), field2 (CharField), field3 (CharField)> ]
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>>> Model2A.objects.extra(select={"select_test": "field1 = 'A1'"}, where=["field1 = 'A1' OR field1 = 'B1'"], order_by = ['-id'] )
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[ <Model2B: id 2, field1 (CharField), field2 (CharField) - Extra: select_test (int)>,
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<Model2A: id 1, field1 (CharField) - Extra: select_test (int)> ]
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>>> o=ModelExtraA.objects.create(field1='A1')
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>>> o=ModelExtraB.objects.create(field1='B1', field2='B2')
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>>> o=ModelExtraC.objects.create(field1='C1', field2='C2', field3='C3')
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>>> o=ModelExtraExternal.objects.create(topic='extra1')
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>>> o=ModelExtraExternal.objects.create(topic='extra2')
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>>> o=ModelExtraExternal.objects.create(topic='extra3')
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>>> ModelExtraA.objects.extra(tables=["polymorphic_modelextraexternal"], select={"topic":"polymorphic_modelextraexternal.topic"}, where=["polymorphic_modelextraa.id = polymorphic_modelextraexternal.id"] )
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[ <ModelExtraA: id 1, field1 (CharField): "A1" - Extra: topic (unicode): "extra1">,
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<ModelExtraB: id 2, field1 (CharField): "B1", field2 (CharField): "B2" - Extra: topic (unicode): "extra2">,
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<ModelExtraC: id 3, field1 (CharField): "C1", field2 (CharField): "C2", field3 (CharField): "C3" - Extra: topic (unicode): "extra3"> ]
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### class filtering, instance_of, not_instance_of
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