Ticket #7539: on_delete_on_update.diff

django/db/models/base.py

@@ -12 +12 @@
-from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned, FieldError
-from django.db.models.fields import AutoField, FieldDoesNotExist
-from django.db.models.fields.related import OneToOneRel, ManyToOneRel, OneToOneField
-
+Fields, Collected
-from django.db.models.options import Options
-
+, IntegrityError
-from django.db.models import signals
+from django.db.models.fields.related import CASCADE, RESTRICT, SET_NULL
-from django.db.models.loading import register_models, get_model
-from django.utils.functional import curry
-from django.utils.encoding import smart_str, force_unicode, smart_unicode
@@ -412 +413 @@
-
-    save_base.alters_data = True
-
-
+fields_to_null, 
-        """
-        Recursively populates seen_objs with all objects related to this
-        object.
@@ -424 +425 @@
-        pk_val = self._get_pk_val()
-        if seen_objs.add(self.__class__, pk_val, self, parent, nullable):
-            return
+            
+        if not getattr(settings, 'ON_DELETE_HANDLED_BY_DB', False):
+            ON_DELETE_NONE_HANDLING = getattr(settings, 'ON_DELETE_NONE_HANDLING', CASCADE)
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-                else:
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-
+            # Handle any ancestors (for the model-inheritance case). We do this by
+            # traversing to the most remote parent classes -- those with no parents
+            # themselves -- and then adding those instances to the collection. That
+            # will include all the child instances down to "self".
+            parent_stack = self._meta.parents.values()
+            while parent_stack:
+                link = parent_stack.pop()
+                parent_obj = getattr(self, link.name)
+                if parent_obj._meta.parents:
+                    parent_stack.extend(parent_obj._meta.parents.values())
+                    continue
+                # At this point, parent_obj is base class (no ancestor models). So
+                # delete it and all its descendents.
+                parent_obj._collect_sub_objects(seen_objs, fields_to_null)
+
-    def delete(self):
-        assert self._get_pk_val() is not None, "%s object can't be deleted because its %s attribute is set to None." % (self._meta.object_name, self._meta.pk.attname)
-
-        # Find all the objects than need to be deleted.
-        seen_objs = CollectedObjects()
-
+
+
-
-        # Actually delete the objects.
-
+, fields_to_null
-
-    delete.alters_data = True
-

django/db/models/fields/related.py

@@ -10 +10 @@
-from django.utils.functional import curry
-from django.core import exceptions
-from django import forms
+from django.conf import settings
-
-try:
-    set
@@ -20 +21 @@
-
-pending_lookups = {}
-
+class _OnDeleteOrUpdateAction(object):
+    pass
+class RESTRICT(_OnDeleteOrUpdateAction):
+    sql = 'RESTRICT'
+class CASCADE(_OnDeleteOrUpdateAction):
+    sql = 'CASCADE'
+class SET_NULL(_OnDeleteOrUpdateAction):
+    sql = 'SET NULL'
+ALLOWED_ON_DELETE_ACTION_TYPES = set([None, CASCADE, RESTRICT, SET_NULL])
+ALLOWED_ON_UPDATE_ACTION_TYPES = ALLOWED_ON_DELETE_ACTION_TYPES.copy()
+
-def add_lazy_relation(cls, field, relation, operation):
-    """
-    Adds a lookup on ``cls`` when a related field is defined using a string,
@@ -584 +596 @@
-
-class ManyToOneRel(object):
-    def __init__(self, to, field_name, related_name=None,
-
+
+
-        try:
-            to._meta
-        except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
@@ -597 +610 @@
-        self.lookup_overrides = lookup_overrides or {}
-        self.multiple = True
-        self.parent_link = parent_link
+        self.on_delete = on_delete
+        self.on_update = on_update
-
-    def get_related_field(self):
-        """
@@ -611 +626 @@
-
-class OneToOneRel(ManyToOneRel):
-    def __init__(self, to, field_name, related_name=None,
-
+
+
-        super(OneToOneRel, self).__init__(to, field_name,
-                related_name=related_name, limit_choices_to=limit_choices_to,
-
+
+
-        self.multiple = False
-
-class ManyToManyRel(object):
@@ -645 +662 @@
-            related_name=kwargs.pop('related_name', None),
-            limit_choices_to=kwargs.pop('limit_choices_to', None),
-            lookup_overrides=kwargs.pop('lookup_overrides', None),
-
+
+
+
-        Field.__init__(self, **kwargs)
-
-        self.db_index = True
@@ -690 +709 @@
-            target = self.rel.to._meta.db_table
-        cls._meta.duplicate_targets[self.column] = (target, "o2m")
-
+        on_delete, on_update = self.rel.on_delete, self.rel.on_update
+        if on_delete not in ALLOWED_ON_DELETE_ACTION_TYPES:
+            raise ValueError("Invalid value 'on_delete=%s' specified for ForeignKey field %s.%s." % (on_delete, cls.__name__, name))
+        if on_update not in ALLOWED_ON_UPDATE_ACTION_TYPES:
+            raise ValueError("Invalid value 'on_update=%s' specified for ForeignKey field %s.%s." % (on_update, cls.__name__, name))
+        if (on_delete == SET_NULL or on_update == SET_NULL) and not self.null:
+            if on_delete == SET_NULL and on_update == SET_NULL:
+                specification = "'on_delete=SET_NULL' and 'on_update=SET_NULL'"
+            elif on_delete == SET_NULL:
+                specification = "'on_delete=SET_NULL'"
+            else:
+                specification = "'on_update=SET_NULL'"
+            raise ValueError("%s specified for ForeignKey field '%s.%s', but the field is not nullable." % (specification, cls.__name__, name))
+        if on_delete is None and getattr(settings, 'ON_DELETE_NONE_HANDLING', CASCADE) == SET_NULL and not self.null:
+            raise ValueError("on_delete=SET_NULL is being used by default (based on the ON_DELETE_NONE_HANDLING setting) for ForeignKey field '%s.%s', but the field is not nullable." % (specification, cls.__name__, name))
+
-    def contribute_to_related_class(self, cls, related):
-        setattr(cls, related.get_accessor_name(), ForeignRelatedObjectsDescriptor(related))
-

django/db/models/__init__.py

@@ -11 +11 @@
-from django.db.models.fields.subclassing import SubfieldBase
-from django.db.models.fields.files import FileField, ImageField
-from django.db.models.fields.related import ForeignKey, OneToOneField, ManyToManyField, ManyToOneRel, ManyToManyRel, OneToOneRel
+from django.db.models.fields.related import CASCADE, RESTRICT, SET_NULL
-from django.db.models import signals
-
-# Admin stages.

django/db/models/query.py

@@ -117 +117 @@
-        """
-        return self.data.keys()
-
+class CollectedFields(object):
+    """
+    A container that stores model objects and fields that need to
+    be nulled to enforce the on_delete=SET_NULL ForeignKey constraint.
+    """
-
+    def __init__(self):
+        self.data = {}
+
+    def add(self, model, pk, obj, field_name):
+        """
+        Adds an item.
+        model is the class of the object being added,
+        pk is the primary key, obj is the object itself, 
+        field_name is the name of the field to be nulled.
+        """
+        d = self.data.setdefault(model, SortedDict())
+        obj, field_names = d.setdefault(pk, (obj, set()))
+        field_names.add(field_name)
+
+    def __contains__(self, key):
+        return self.data.__contains__(key)
+
+    def __getitem__(self, key):
+        return self.data[key]
+
+    def __nonzero__(self):
+        return bool(self.data)
+
+    def iteritems(self):
+        return self.data.iteritems()
+
+    def iterkeys(self):
+        return self.data.iterkeys()
+
+    def itervalues(self):
+        return self.data.itervalues()
+        
-class QuerySet(object):
-    """
-    Represents a lazy database lookup for a set of objects.
@@ -427 +464 @@
-            # Collect all the objects to be deleted in this chunk, and all the
-            # objects that are related to the objects that are to be deleted.
-            seen_objs = CollectedObjects()
+            fields_to_null = CollectedFields()
-            for object in del_query[:CHUNK_SIZE]:
-
+, fields_to_null
-
-            if not seen_objs:
-                break
-
+, fields_to_null
-
-        # Clear the result cache, in case this QuerySet gets reused.
-        self._result_cache = None
@@ -951 +989 @@
-                setattr(obj, f.get_cache_name(), rel_obj)
-    return obj, index_end
-
-
-
+
-    """
-    Iterate through a list of seen classes, and remove any instances that are
-    referred to.
@@ -992 +1029 @@
-                    update_query.clear_related(field, pk_list)
-
-    # Now delete the actual data.
+    for cls, cls_dct in fields_to_null.iteritems():
+        update_query = sql.UpdateQuery(cls, connection)
+        field_dict = {}
+        for pk, (_, field_names) in cls_dct.iteritems():
+            for field_name in field_names:
+                pk_set = field_dict.setdefault(field_name, set())
+                pk_set.add(pk)
+        for field_name, pk_set in field_dict.iteritems():
+            update_query.clear_related(cls._meta.get_field_by_name(field_name)[0], list(pk_set))
-    for cls in ordered_classes:
-        items = obj_pairs[cls]
-        items.reverse()
@@ -1003 +1049 @@
-        # Last cleanup; set NULLs where there once was a reference to the
-        # object, NULL the primary key of the found objects, and perform
-        # post-notification.
+        for cls, cls_dct in fields_to_null.iteritems():
+            for instance, field_names in cls_dct.itervalues():
+                for field_name in field_names:
+                    field = cls._meta.get_field_by_name(field_name)[0]
+                    setattr(instance, field.attname, None)
-        for pk_val, instance in items:
-            for field in cls._meta.fields:
-                if field.rel and field.null and field.rel.to in seen_objs:

django/db/backends/creation.py

@@ -94 +94 @@
-        "Return the SQL snippet defining the foreign key reference for a field"
-        qn = self.connection.ops.quote_name
-        if field.rel.to in known_models:
+            on_delete_clause, on_update_clause = self.on_delete_and_update_clauses(style, field)
-            output = [style.SQL_KEYWORD('REFERENCES') + ' ' + \
-                style.SQL_TABLE(qn(field.rel.to._meta.db_table)) + ' (' + \
-                style.SQL_FIELD(qn(field.rel.to._meta.get_field(field.rel.field_name).column)) + ')' +
+                on_delete_clause + on_update_clause +
-                self.connection.ops.deferrable_sql()
-            ]
-            pending = False
@@ -117 +119 @@
-        opts = model._meta
-        if model in pending_references:
-            for rel_class, f in pending_references[model]:
+                on_delete_clause, on_update_clause = self.on_delete_and_update_clauses(style, f)
-                rel_opts = rel_class._meta
-                r_table = rel_opts.db_table
-                r_col = f.column
@@ -125 +128 @@
-                # For MySQL, r_name must be unique in the first 64 characters.
-                # So we are careful with character usage here.
-                r_name = '%s_refs_%s_%x' % (r_col, col, abs(hash((r_table, table))))
-
+%s%s
-                    (qn(r_table), qn(truncate_name(r_name, self.connection.ops.max_name_length())),
-                    qn(r_col), qn(table), qn(col),
+                    on_delete_clause, on_update_clause,
-                    self.connection.ops.deferrable_sql()))
-            del pending_references[model]
-        return final_output
-
+    def on_delete_and_update_clauses(self, style, foreign_key_field):
+        on_delete_clause = ''
+        try:
+            on_delete = getattr(foreign_key_field, 'ON_DELETE_HANDLED_BY_DB') #USED FOR UNIT TESTING ONLY (see comment in modeltests/on_delete_and_update_db/models.py)
+        except AttributeError:
+            on_delete = getattr(settings, 'ON_DELETE_HANDLED_BY_DB', False)
+        if on_delete:
+            on_delete = getattr(foreign_key_field.rel, 'on_delete', None)
+            if on_delete:
+                on_delete_clause = style.SQL_KEYWORD(' ON DELETE %s' % foreign_key_field.rel.on_delete.sql)
+            
+        on_update_clause = ''
+        try:
+            on_update = getattr(foreign_key_field, 'ON_UPDATE_HANDLED_BY_DB') #USED FOR UNIT TESTING ONLY; (see comment in modeltests/on_delete_and_update_db/models.py)
+        except AttributeError:
+            on_update = getattr(settings, 'ON_UPDATE_HANDLED_BY_DB', False)
+        if on_update:
+            on_update = getattr(foreign_key_field.rel, 'on_update', None)
+            if on_update:
+                on_update_clause = style.SQL_KEYWORD(' ON UPDATE %s' % foreign_key_field.rel.on_update.sql)
+
+        return on_delete_clause, on_update_clause
+        
-    def sql_for_many_to_many(self, model, style):
-        "Return the CREATE TABLE statments for all the many-to-many tables defined on a model"
-        output = []

tests/modeltests/on_delete_and_on_update_db/tests.py

@@ +1 @@
+"""
+Test ON DELETE and ON UPDATE behavior for foreign keys
+when it's handled by the database
+(ie. when settings.ON_DELETE_HANDLED_BY_DB=True
+and settings.ON_UPDATE_HANDLED_BY_DB=True).
+"""
+
+from django.conf import settings
+from django.db import IntegrityError
+from django.test import TestCase
+
+from models import *
+
+
+class ON_DELETE_Tests(TestCase):
+    def setUp(self):
+        self._old = getattr(settings, 'ON_DELETE_HANDLED_BY_DB', False)
+        settings.ON_DELETE_HANDLED_BY_DB = True
+
+    def tearDown(self):
+        settings.ON_DELETE_HANDLED_BY_DB = self._old
+
+    def test_on_delete_SET_NULL_requires_nullable_field(self):
+        try:
+            class Test(models.Model):
+                fk = models.ForeignKey(Data, to_field='data', on_delete=models.SET_NULL)
+        except ValueError, e:
+            self.assertEqual(str(e), "'on_delete=SET_NULL' specified for ForeignKey field 'Test.fk', but the field is not nullable.")
+        else:
+            self.assertTrue(False, 'Expected exception not raised.')
+        
+    def test_on_delete_None(self):
+        #SQL behavior is to default to RESTRICT if no ON DELETE clause is specified
+        FKModel = FK_on_delete_None
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        self.assertRaises(IntegrityError, data.delete)
+
+    def test_on_delete_CASCADE(self):
+        FKModel = FK_on_delete_CASCADE
+        data = Data.objects.create(data=1)
+        fk_id = FKModel.objects.create(fk=data).id
+        self.assertEqual(data, FKModel.objects.get(id=fk_id).fk)
+        data.delete()
+        self.assertRaises(FKModel.DoesNotExist, FKModel.objects.get, id=fk_id)
+
+    def test_on_delete_RESTRICT(self):
+        FKModel = FK_on_delete_RESTRICT
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        self.assertRaises(IntegrityError, data.delete)
+
+    def test_on_delete_SET_NULL(self):
+        FKModel = FK_on_delete_SET_NULL
+        data = Data.objects.create(data=1)
+        fk_id = FKModel.objects.create(fk=data).id
+        self.assertEqual(data, FKModel.objects.get(id=fk_id).fk)
+        self.assertEqual(1, FKModel.objects.get(id=fk_id).fk_id)
+        data.delete()
+        self.assertEqual(None, FKModel.objects.get(id=fk_id).fk)
+        self.assertEqual(None, FKModel.objects.get(id=fk_id).fk_id)
+
+
+class ON_UPDATE_Tests(TestCase):
+    def setUp(self):
+        self._old = getattr(settings, 'ON_UPDATE_HANDLED_BY_DB', False)
+        settings.ON_UPDATE_HANDLED_BY_DB = True
+
+    def tearDown(self):
+        settings.ON_UPDATE_HANDLED_BY_DB = self._old
+
+    def test_on_update_SET_NULL_requires_nullable_field(self):
+        try:
+            class Test(models.Model):
+                fk = models.ForeignKey(Data, to_field='data', on_update=models.SET_NULL)
+        except ValueError, e:
+            self.assertEqual(str(e), "'on_update=SET_NULL' specified for ForeignKey field 'Test.fk', but the field is not nullable.")
+        else:
+            self.assertTrue(False, 'Expected exception not raised.')
+        
+    def test_on_update_None(self):
+        #SQL behavior is to default to RESTRICT if no ON DELETE clause is specified
+        FKModel = FK_on_update_None
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        data.data += 1
+        self.assertRaises(IntegrityError, data.save)
+
+    def test_on_update_CASCADE(self):
+        FKModel = FK_on_update_CASCADE
+        data = Data.objects.create(data=1)
+        fk_id = FKModel.objects.create(fk=data).id
+        self.assertEqual(1, FKModel.objects.get(id=fk_id).fk_id)
+        data.data += 1
+        data.save()
+        self.assertEqual(2, FKModel.objects.get(id=fk_id).fk_id)
+
+    def test_on_update_RESTRICT(self):
+        FKModel = FK_on_update_RESTRICT
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        data.data += 1
+        self.assertRaises(IntegrityError, data.save)
+
+    def test_on_update_SET_NULL(self):
+        FKModel = FK_on_update_SET_NULL
+        data = Data.objects.create(data=1)
+        fk_id = FKModel.objects.create(fk=data).id
+        self.assertEqual(data, FKModel.objects.get(id=fk_id).fk)
+        self.assertEqual(1, FKModel.objects.get(id=fk_id).fk_id)
+        data.data += 1
+        data.save()
+        self.assertEqual(None, FKModel.objects.get(id=fk_id).fk)
+        self.assertEqual(None, FKModel.objects.get(id=fk_id).fk_id)
+

tests/modeltests/on_delete_and_on_update_db/models.py

@@ +1 @@
+"""
+Test ON DELETE and ON UPDATE behavior for foreign keys
+when it's handled by the database.
+"""
+
+from django.db import models
+
+
+#Note: all the lines marked "Used for unit testing only" mean:
+#Some tests (the ones modeltests/on_delete_and_update_db/test.py) 
+#need to force SQL generation to include ON UPDATE and ON DELETE clauses,
+#while others (the ones modeltests/on_delete_and_update_django/test.py) 
+#need to force the SQL not to include these clauses. 
+#Normally the SQL generation is controlled by the settings.py file; 
+#however, usually the database is created all at once when the unit 
+#tests are started, and it uses the settings at the time that happens;
+#there is no way (that I found) to have different settings for different 
+#unit tests. So, this method of controlling it field-by-field was
+#added instead; it is intended to be used only by the unit tests.
+
+
+class Data(models.Model):
+    data = models.IntegerField(unique=True)
+
+
+class FK_on_delete_None(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_delete=None)
+    fk.ON_DELETE_HANDLED_BY_DB = True #Used for unit testing only (see comment above)
+
+class FK_on_delete_CASCADE(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_delete=models.CASCADE)
+    fk.ON_DELETE_HANDLED_BY_DB = True #Used for unit testing only (see comment above)
+
+class FK_on_delete_RESTRICT(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_delete=models.RESTRICT)
+    fk.ON_DELETE_HANDLED_BY_DB = True #Used for unit testing only (see comment above)
+
+class FK_on_delete_SET_NULL(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', null=True, on_delete=models.SET_NULL)
+    fk.ON_DELETE_HANDLED_BY_DB = True #Used for unit testing only (see comment above)
+
+
+class FK_on_update_None(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_update=None)
+    fk.ON_UPDATE_HANDLED_BY_DB = True #Used for unit testing only (see comment above)
+
+class FK_on_update_CASCADE(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_update=models.CASCADE)
+    fk.ON_UPDATE_HANDLED_BY_DB = True #Used for unit testing only (see comment above)
+
+class FK_on_update_RESTRICT(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_update=models.RESTRICT)
+    fk.ON_UPDATE_HANDLED_BY_DB = True #Used for unit testing only (see comment above)
+
+class FK_on_update_SET_NULL(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', null=True, on_update=models.SET_NULL)
+    fk.ON_UPDATE_HANDLED_BY_DB = True #Used for unit testing only (see comment above)

tests/modeltests/on_delete_and_on_update_django/tests.py

@@ +1 @@
+"""
+Test ON DELETE and ON UPDATE behavior for foreign keys
+when it's handled by the Django
+(ie. when settings.ON_DELETE_HANDLED_BY_DB=False
+and settings.ON_UPDATE_HANDLED_BY_DB=False).
+"""
+
+from django.conf import settings
+from django.db import IntegrityError
+from django.db.models.fields.related import CASCADE, RESTRICT, SET_NULL
+from django.test import TestCase
+
+from models import *
+
+
+class ON_DELETE_Tests(TestCase):
+    def setUp(self):
+        self._old_ON_DELETE_HANDLED_BY_DB = getattr(settings, 'ON_DELETE_HANDLED_BY_DB', False)
+        settings.ON_DELETE_HANDLED_BY_DB = False
+        self._old_ON_DELETE_NONE_HANDLING = getattr(settings, 'ON_DELETE_NONE_HANDLING', CASCADE)
+    
+    def tearDown(self):
+        settings.ON_DELETE_HANDLED_BY_DB = self._old_ON_DELETE_HANDLED_BY_DB
+        settings.ON_DELETE_NONE_HANDLING = self._old_ON_DELETE_NONE_HANDLING
+    
+    def test_on_delete_SET_NULL_requires_nullable_field(self):
+        try:
+            class Test(models.Model):
+                fk = models.ForeignKey(Data, to_field='data', on_delete=models.SET_NULL)
+        except ValueError, e:
+            self.assertEqual(str(e), "'on_delete=SET_NULL' specified for ForeignKey field 'Test.fk', but the field is not nullable.")
+        else:
+            self.assertTrue(False, 'Expected exception not raised.')
+    
+    def test_on_delete_None_CASCADE(self):
+        FKModel = FK_on_delete_None
+        settings.ON_DELETE_NONE_HANDLING = CASCADE
+        data = Data.objects.create(data=1)
+        fk_id = FKModel.objects.create(fk=data).id
+        FKModel.objects.get(id=fk_id)
+        data.delete()
+        self.assertRaises(FKModel.DoesNotExist, FKModel.objects.get, id=fk_id)
+    
+    def test_on_delete_None_SET_NULL(self):
+        FKModel = FK_on_delete_None
+        settings.ON_DELETE_NONE_HANDLING = SET_NULL
+        data = Data.objects.create(data=1)
+        fk_id = FKModel.objects.create(fk=data).id
+        self.assertEqual(data, FKModel.objects.get(id=fk_id).fk)
+        self.assertEqual(1, FKModel.objects.get(id=fk_id).fk_id)
+        data.delete()
+        self.assertEqual(None, FKModel.objects.get(id=fk_id).fk)
+        self.assertEqual(None, FKModel.objects.get(id=fk_id).fk_id)
+    
+    def test_on_delete_None_SET_NULL_NoNull(self):
+        FKModel = FK_on_delete_None_NoNull
+        settings.ON_DELETE_NONE_HANDLING = SET_NULL
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data).id
+        self.assertRaises(IntegrityError, data.delete)
+    
+    def test_on_delete_None_RESTRICT(self):
+        FKModel = FK_on_delete_None
+        settings.ON_DELETE_NONE_HANDLING = RESTRICT
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        self.assertRaises(IntegrityError, data.delete)
+    
+    def test_on_delete_CASCADE(self):
+        FKModel = FK_on_delete_CASCADE
+        data = Data.objects.create(data=1)
+        fk_id = FKModel.objects.create(fk=data).id
+        FKModel.objects.get(id=fk_id)
+        data.delete()
+        self.assertRaises(FKModel.DoesNotExist, FKModel.objects.get, id=fk_id)
+    
+    def test_on_delete_RESTRICT(self):
+        FKModel = FK_on_delete_RESTRICT
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        self.assertRaises(IntegrityError, data.delete)
+    
+    def test_on_delete_SET_NULL(self):
+        FKModel = FK_on_delete_SET_NULL
+        data = Data.objects.create(data=1)
+        fk_id = FKModel.objects.create(fk=data).id
+        self.assertEqual(data, FKModel.objects.get(id=fk_id).fk)
+        self.assertEqual(1, FKModel.objects.get(id=fk_id).fk_id)
+        data.delete()
+        self.assertEqual(None, FKModel.objects.get(id=fk_id).fk)
+        self.assertEqual(None, FKModel.objects.get(id=fk_id).fk_id)
+
+
+class ON_UPDATE_Tests(TestCase):
+    def setUp(self):
+        self._old_ON_UPDATE_HANDLED_BY_DB = getattr(settings, 'ON_UPDATE_HANDLED_BY_DB', False)
+        settings.ON_UPDATE_HANDLED_BY_DB = False
+    
+    def tearDown(self):
+        settings.ON_UPDATE_HANDLED_BY_DB = self._old_ON_UPDATE_HANDLED_BY_DB
+    
+    def test_on_update_SET_NULL_requires_nullable_field(self):
+        try:
+            class Test(models.Model):
+                fk = models.ForeignKey(Data, to_field='data', on_update=models.SET_NULL)
+        except ValueError, e:
+            self.assertEqual(str(e), "'on_update=SET_NULL' specified for ForeignKey field 'Test.fk', but the field is not nullable.")
+        else:
+            self.assertTrue(False, 'Expected exception not raised.')
+    
+    def test_on_update_None(self):
+        #Currently Django has no ON UPDATE behavior at all,
+        #so the default SQL behavior when no ON UPDATE clause
+        #is specified takes over: it acts like ON UPDATE RESTRICT.
+        FKModel = FK_on_update_None
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        data.data += 1
+        self.assertRaises(IntegrityError, data.save)
+    
+    def test_on_update_CASCADE(self):
+        #Currently Django has no ON UPDATE behavior at all,
+        #so the default SQL behavior when no ON UPDATE clause
+        #is specified takes over: it acts like ON UPDATE RESTRICT.
+        FKModel = FK_on_update_CASCADE
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        data.data += 1
+        self.assertRaises(IntegrityError, data.save)
+    
+    def test_on_update_RESTRICT(self):
+        #Currently Django has no ON UPDATE behavior at all,
+        #so the default SQL behavior when no ON UPDATE clause
+        #is specified takes over: it acts like ON UPDATE RESTRICT.
+        FKModel = FK_on_update_RESTRICT
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        data.data += 1
+        self.assertRaises(IntegrityError, data.save)
+    
+    def test_on_update_SET_NULL(self):
+        #Currently Django has no ON UPDATE behavior at all,
+        #so the default SQL behavior when no ON UPDATE clause
+        #is specified takes over: it acts like ON UPDATE RESTRICT.
+        FKModel = FK_on_update_SET_NULL
+        data = Data.objects.create(data=1)
+        FKModel.objects.create(fk=data)
+        data.data += 1
+        self.assertRaises(IntegrityError, data.save)

tests/modeltests/on_delete_and_on_update_django/models.py

@@ +1 @@
+"""
+Test ON DELETE and ON UPDATE behavior for foreign keys
+when it's handled by the Django.
+"""
+
+from django.db import models
+
+
+#Note: for the meaning of the lines marked "Used for unit testing only",
+#see comment in modeltests/on_delete_and_update_db/models.py
+
+
+class Data(models.Model):
+    data = models.IntegerField(unique=True)
+
+
+class FK_on_delete_None(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', null=True, on_delete=None)
+    fk.ON_DELETE_HANDLED_BY_DB = False #Used for unit testing only (see comment above)
+
+class FK_on_delete_None_NoNull(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_delete=None)
+    fk.ON_DELETE_HANDLED_BY_DB = False #Used for unit testing only (see comment above)
+
+class FK_on_delete_CASCADE(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_delete=models.CASCADE)
+    fk.ON_DELETE_HANDLED_BY_DB = False #Used for unit testing only (see comment above)
+
+class FK_on_delete_RESTRICT(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_delete=models.RESTRICT)
+    fk.ON_DELETE_HANDLED_BY_DB = False #Used for unit testing only (see comment above)
+
+class FK_on_delete_SET_NULL(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', null=True, on_delete=models.SET_NULL)
+    fk.ON_DELETE_HANDLED_BY_DB = False #Used for unit testing only (see comment above)
+
+
+class FK_on_update_None(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_update=None)
+    fk.ON_UPDATE_HANDLED_BY_DB = False #Used for unit testing only (see comment above)
+
+class FK_on_update_CASCADE(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_update=models.CASCADE)
+    fk.ON_UPDATE_HANDLED_BY_DB = False #Used for unit testing only (see comment above)
+
+class FK_on_update_RESTRICT(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', on_update=models.RESTRICT)
+    fk.ON_UPDATE_HANDLED_BY_DB = False #Used for unit testing only (see comment above)
+
+class FK_on_update_SET_NULL(models.Model):
+    fk = models.ForeignKey(Data, to_field='data', null=True, on_update=models.SET_NULL)
+    fk.ON_UPDATE_HANDLED_BY_DB = False #Used for unit testing only (see comment above)
+    

tests/modeltests/delete/models.py

@@ -46 +46 @@
-
-## First, test the CollectedObjects data structure directly
-
-
+Fields, Collected
-
->>> g = CollectedObjects()
->>> g.add("key1", 1, "item1", None)
@@ -112 +112 @@
->>> d1 = D(c=c1, a=a1)
->>> d1.save()
-
- = CollectedObject
-
+, p = CollectedObjects(), CollectedField
+, p
->>> o.keys()
-[<class 'modeltests.delete.models.D'>, <class 'modeltests.delete.models.C'>, <class 'modeltests.delete.models.B'>, <class 'modeltests.delete.models.A'>]
->>> a1.delete()
@@ -131 +131 @@
->>> d2 = D(c=c2, a=a2)
->>> d2.save()
-
- = CollectedObject
-
+, p = CollectedObjects(), CollectedField
+, p
->>> o.keys()
-[<class 'modeltests.delete.models.D'>, <class 'modeltests.delete.models.C'>, <class 'modeltests.delete.models.B'>, <class 'modeltests.delete.models.A'>]
->>> a2.delete()
@@ -163 +163 @@
-# Since E.f is nullable, we should delete F first (after nulling out
-# the E.f field), then E.
-
- = CollectedObject
-
+, p = CollectedObjects(), CollectedField
+, p
->>> o.keys()
-[<class 'modeltests.delete.models.F'>, <class 'modeltests.delete.models.E'>]
-
@@ -179 +179 @@
-
-# Same deal as before, though we are starting from the other object.
-
- = CollectedObject
-
+, p = CollectedObjects(), CollectedField
+, p
->>> o.keys()
-[<class 'modeltests.delete.models.F'>, <class 'modeltests.delete.models.E'>]