""" 26. Invalid models This example exists purely to point out errors in models. """ from django.contrib.contenttypes import generic from django.db import models class FieldErrors(models.Model): charfield = models.CharField() charfield2 = models.CharField(max_length=-1) charfield3 = models.CharField(max_length="bad") decimalfield = models.DecimalField() decimalfield2 = models.DecimalField(max_digits=-1, decimal_places=-1) decimalfield3 = models.DecimalField(max_digits="bad", decimal_places="bad") decimalfield4 = models.DecimalField(max_digits=9, decimal_places=10) decimalfield5 = models.DecimalField(max_digits=10, decimal_places=10) filefield = models.FileField() choices = models.CharField(max_length=10, choices='bad') choices2 = models.CharField(max_length=10, choices=[(1,2,3),(1,2,3)]) index = models.CharField(max_length=10, db_index='bad') field_ = models.CharField(max_length=10) nullbool = models.BooleanField(null=True) class Target(models.Model): tgt_safe = models.CharField(max_length=10) clash1 = models.CharField(max_length=10) clash2 = models.CharField(max_length=10) clash1_set = models.CharField(max_length=10) class Clash1(models.Model): src_safe = models.CharField(max_length=10) foreign = models.ForeignKey(Target) m2m = models.ManyToManyField(Target) class Clash2(models.Model): src_safe = models.CharField(max_length=10) foreign_1 = models.ForeignKey(Target, related_name='id') foreign_2 = models.ForeignKey(Target, related_name='src_safe') m2m_1 = models.ManyToManyField(Target, related_name='id') m2m_2 = models.ManyToManyField(Target, related_name='src_safe') class Target2(models.Model): clash3 = models.CharField(max_length=10) foreign_tgt = models.ForeignKey(Target) clashforeign_set = models.ForeignKey(Target) m2m_tgt = models.ManyToManyField(Target) clashm2m_set = models.ManyToManyField(Target) class Clash3(models.Model): src_safe = models.CharField(max_length=10) foreign_1 = models.ForeignKey(Target2, related_name='foreign_tgt') foreign_2 = models.ForeignKey(Target2, related_name='m2m_tgt') m2m_1 = models.ManyToManyField(Target2, related_name='foreign_tgt') m2m_2 = models.ManyToManyField(Target2, related_name='m2m_tgt') class ClashForeign(models.Model): foreign = models.ForeignKey(Target2) class ClashM2M(models.Model): m2m = models.ManyToManyField(Target2) class SelfClashForeign(models.Model): src_safe = models.CharField(max_length=10) selfclashforeign = models.CharField(max_length=10) selfclashforeign_set = models.ForeignKey("SelfClashForeign") foreign_1 = models.ForeignKey("SelfClashForeign", related_name='id') foreign_2 = models.ForeignKey("SelfClashForeign", related_name='src_safe') class ValidM2M(models.Model): src_safe = models.CharField(max_length=10) validm2m = models.CharField(max_length=10) # M2M fields are symmetrical by default. Symmetrical M2M fields # on self don't require a related accessor, so many potential # clashes are avoided. validm2m_set = models.ManyToManyField("self") m2m_1 = models.ManyToManyField("self", related_name='id') m2m_2 = models.ManyToManyField("self", related_name='src_safe') m2m_3 = models.ManyToManyField('self') m2m_4 = models.ManyToManyField('self') class SelfClashM2M(models.Model): src_safe = models.CharField(max_length=10) selfclashm2m = models.CharField(max_length=10) # Non-symmetrical M2M fields _do_ have related accessors, so # there is potential for clashes. selfclashm2m_set = models.ManyToManyField("self", symmetrical=False) m2m_1 = models.ManyToManyField("self", related_name='id', symmetrical=False) m2m_2 = models.ManyToManyField("self", related_name='src_safe', symmetrical=False) m2m_3 = models.ManyToManyField('self', symmetrical=False) m2m_4 = models.ManyToManyField('self', symmetrical=False) class Model(models.Model): "But it's valid to call a model Model." year = models.PositiveIntegerField() #1960 make = models.CharField(max_length=10) #Aston Martin name = models.CharField(max_length=10) #DB 4 GT class Car(models.Model): colour = models.CharField(max_length=5) model = models.ForeignKey(Model) class MissingRelations(models.Model): rel1 = models.ForeignKey("Rel1") rel2 = models.ManyToManyField("Rel2") class MissingManualM2MModel(models.Model): name = models.CharField(max_length=5) missing_m2m = models.ManyToManyField(Model, through="MissingM2MModel") class Person(models.Model): name = models.CharField(max_length=5) class Group(models.Model): name = models.CharField(max_length=5) primary = models.ManyToManyField(Person, through="Membership", related_name="primary") secondary = models.ManyToManyField(Person, through="Membership", related_name="secondary") tertiary = models.ManyToManyField(Person, through="RelationshipDoubleFK", related_name="tertiary") class GroupTwo(models.Model): name = models.CharField(max_length=5) primary = models.ManyToManyField(Person, through="Membership") secondary = models.ManyToManyField(Group, through="MembershipMissingFK") class Membership(models.Model): person = models.ForeignKey(Person) group = models.ForeignKey(Group) not_default_or_null = models.CharField(max_length=5) class MembershipMissingFK(models.Model): person = models.ForeignKey(Person) class PersonSelfRefM2M(models.Model): name = models.CharField(max_length=5) friends = models.ManyToManyField('self', through="Relationship") too_many_friends = models.ManyToManyField('self', through="RelationshipTripleFK") class PersonSelfRefM2MExplicit(models.Model): name = models.CharField(max_length=5) friends = models.ManyToManyField('self', through="ExplicitRelationship", symmetrical=True) class Relationship(models.Model): first = models.ForeignKey(PersonSelfRefM2M, related_name="rel_from_set") second = models.ForeignKey(PersonSelfRefM2M, related_name="rel_to_set") date_added = models.DateTimeField() class ExplicitRelationship(models.Model): first = models.ForeignKey(PersonSelfRefM2MExplicit, related_name="rel_from_set") second = models.ForeignKey(PersonSelfRefM2MExplicit, related_name="rel_to_set") date_added = models.DateTimeField() class RelationshipTripleFK(models.Model): first = models.ForeignKey(PersonSelfRefM2M, related_name="rel_from_set_2") second = models.ForeignKey(PersonSelfRefM2M, related_name="rel_to_set_2") third = models.ForeignKey(PersonSelfRefM2M, related_name="too_many_by_far") date_added = models.DateTimeField() class RelationshipDoubleFK(models.Model): first = models.ForeignKey(Person, related_name="first_related_name") second = models.ForeignKey(Person, related_name="second_related_name") third = models.ForeignKey(Group, related_name="rel_to_set") date_added = models.DateTimeField() class AbstractModel(models.Model): name = models.CharField(max_length=10) class Meta: abstract = True class AbstractRelationModel(models.Model): fk1 = models.ForeignKey('AbstractModel') fk2 = models.ManyToManyField('AbstractModel') class UniqueM2M(models.Model): """ Model to test for unique ManyToManyFields, which are invalid. """ unique_people = models.ManyToManyField(Person, unique=True) class NonUniqueFKTarget1(models.Model): """ Model to test for non-unique FK target in yet-to-be-defined model: expect an error """ tgt = models.ForeignKey('FKTarget', to_field='bad') class UniqueFKTarget1(models.Model): """ Model to test for unique FK target in yet-to-be-defined model: expect no error """ tgt = models.ForeignKey('FKTarget', to_field='good') class FKTarget(models.Model): bad = models.IntegerField() good = models.IntegerField(unique=True) class NonUniqueFKTarget2(models.Model): """ Model to test for non-unique FK target in previously seen model: expect an error """ tgt = models.ForeignKey(FKTarget, to_field='bad') class UniqueFKTarget2(models.Model): """ Model to test for unique FK target in previously seen model: expect no error """ tgt = models.ForeignKey(FKTarget, to_field='good') class NonExistingOrderingWithSingleUnderscore(models.Model): class Meta: ordering = ("does_not_exist",) class Tag(models.Model): name = models.CharField("name", max_length=20) class TaggedObject(models.Model): object_id = models.PositiveIntegerField("Object ID") tag = models.ForeignKey(Tag) content_object = generic.GenericForeignKey() class UserTaggedObject(models.Model): object_tag = models.ForeignKey(TaggedObject) class ArticleAttachment(models.Model): tags = generic.GenericRelation(TaggedObject) user_tags = generic.GenericRelation(UserTaggedObject) model_errors = """invalid_models.fielderrors: "charfield": CharFields require a "max_length" attribute that is a positive integer. invalid_models.fielderrors: "charfield2": CharFields require a "max_length" attribute that is a positive integer. invalid_models.fielderrors: "charfield3": CharFields require a "max_length" attribute that is a positive integer. invalid_models.fielderrors: "decimalfield": DecimalFields require a "decimal_places" attribute that is a non-negative integer. invalid_models.fielderrors: "decimalfield": DecimalFields require a "max_digits" attribute that is a positive integer. invalid_models.fielderrors: "decimalfield2": DecimalFields require a "decimal_places" attribute that is a non-negative integer. invalid_models.fielderrors: "decimalfield2": DecimalFields require a "max_digits" attribute that is a positive integer. invalid_models.fielderrors: "decimalfield3": DecimalFields require a "decimal_places" attribute that is a non-negative integer. invalid_models.fielderrors: "decimalfield3": DecimalFields require a "max_digits" attribute that is a positive integer. invalid_models.fielderrors: "decimalfield4": DecimalFields require a "max_digits" attribute value that is greater than the value of the "decimal_places" attribute. invalid_models.fielderrors: "decimalfield5": DecimalFields require a "max_digits" attribute value that is greater than the value of the "decimal_places" attribute. invalid_models.fielderrors: "filefield": FileFields require an "upload_to" attribute. invalid_models.fielderrors: "choices": "choices" should be iterable (e.g., a tuple or list). invalid_models.fielderrors: "choices2": "choices" should be a sequence of two-tuples. invalid_models.fielderrors: "choices2": "choices" should be a sequence of two-tuples. invalid_models.fielderrors: "index": "db_index" should be either None, True or False. invalid_models.fielderrors: "field_": Field names cannot end with underscores, because this would lead to ambiguous queryset filters. invalid_models.fielderrors: "nullbool": BooleanFields do not accept null values. Use a NullBooleanField instead. invalid_models.clash1: Accessor for field 'foreign' clashes with field 'Target.clash1_set'. Add a related_name argument to the definition for 'foreign'. invalid_models.clash1: Accessor for field 'foreign' clashes with related m2m field 'Target.clash1_set'. Add a related_name argument to the definition for 'foreign'. invalid_models.clash1: Reverse query name for field 'foreign' clashes with field 'Target.clash1'. Add a related_name argument to the definition for 'foreign'. invalid_models.clash1: Accessor for m2m field 'm2m' clashes with field 'Target.clash1_set'. Add a related_name argument to the definition for 'm2m'. invalid_models.clash1: Accessor for m2m field 'm2m' clashes with related field 'Target.clash1_set'. Add a related_name argument to the definition for 'm2m'. invalid_models.clash1: Reverse query name for m2m field 'm2m' clashes with field 'Target.clash1'. Add a related_name argument to the definition for 'm2m'. invalid_models.clash2: Accessor for field 'foreign_1' clashes with field 'Target.id'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.clash2: Accessor for field 'foreign_1' clashes with related m2m field 'Target.id'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.clash2: Reverse query name for field 'foreign_1' clashes with field 'Target.id'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.clash2: Reverse query name for field 'foreign_1' clashes with related m2m field 'Target.id'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.clash2: Accessor for field 'foreign_2' clashes with related m2m field 'Target.src_safe'. Add a related_name argument to the definition for 'foreign_2'. invalid_models.clash2: Reverse query name for field 'foreign_2' clashes with related m2m field 'Target.src_safe'. Add a related_name argument to the definition for 'foreign_2'. invalid_models.clash2: Accessor for m2m field 'm2m_1' clashes with field 'Target.id'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.clash2: Accessor for m2m field 'm2m_1' clashes with related field 'Target.id'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.clash2: Reverse query name for m2m field 'm2m_1' clashes with field 'Target.id'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.clash2: Reverse query name for m2m field 'm2m_1' clashes with related field 'Target.id'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.clash2: Accessor for m2m field 'm2m_2' clashes with related field 'Target.src_safe'. Add a related_name argument to the definition for 'm2m_2'. invalid_models.clash2: Reverse query name for m2m field 'm2m_2' clashes with related field 'Target.src_safe'. Add a related_name argument to the definition for 'm2m_2'. invalid_models.clash3: Accessor for field 'foreign_1' clashes with field 'Target2.foreign_tgt'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.clash3: Accessor for field 'foreign_1' clashes with related m2m field 'Target2.foreign_tgt'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.clash3: Reverse query name for field 'foreign_1' clashes with field 'Target2.foreign_tgt'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.clash3: Reverse query name for field 'foreign_1' clashes with related m2m field 'Target2.foreign_tgt'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.clash3: Accessor for field 'foreign_2' clashes with m2m field 'Target2.m2m_tgt'. Add a related_name argument to the definition for 'foreign_2'. invalid_models.clash3: Accessor for field 'foreign_2' clashes with related m2m field 'Target2.m2m_tgt'. Add a related_name argument to the definition for 'foreign_2'. invalid_models.clash3: Reverse query name for field 'foreign_2' clashes with m2m field 'Target2.m2m_tgt'. Add a related_name argument to the definition for 'foreign_2'. invalid_models.clash3: Reverse query name for field 'foreign_2' clashes with related m2m field 'Target2.m2m_tgt'. Add a related_name argument to the definition for 'foreign_2'. invalid_models.clash3: Accessor for m2m field 'm2m_1' clashes with field 'Target2.foreign_tgt'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.clash3: Accessor for m2m field 'm2m_1' clashes with related field 'Target2.foreign_tgt'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.clash3: Reverse query name for m2m field 'm2m_1' clashes with field 'Target2.foreign_tgt'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.clash3: Reverse query name for m2m field 'm2m_1' clashes with related field 'Target2.foreign_tgt'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.clash3: Accessor for m2m field 'm2m_2' clashes with m2m field 'Target2.m2m_tgt'. Add a related_name argument to the definition for 'm2m_2'. invalid_models.clash3: Accessor for m2m field 'm2m_2' clashes with related field 'Target2.m2m_tgt'. Add a related_name argument to the definition for 'm2m_2'. invalid_models.clash3: Reverse query name for m2m field 'm2m_2' clashes with m2m field 'Target2.m2m_tgt'. Add a related_name argument to the definition for 'm2m_2'. invalid_models.clash3: Reverse query name for m2m field 'm2m_2' clashes with related field 'Target2.m2m_tgt'. Add a related_name argument to the definition for 'm2m_2'. invalid_models.clashforeign: Accessor for field 'foreign' clashes with field 'Target2.clashforeign_set'. Add a related_name argument to the definition for 'foreign'. invalid_models.clashm2m: Accessor for m2m field 'm2m' clashes with m2m field 'Target2.clashm2m_set'. Add a related_name argument to the definition for 'm2m'. invalid_models.target2: Accessor for field 'foreign_tgt' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'foreign_tgt'. invalid_models.target2: Accessor for field 'foreign_tgt' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'foreign_tgt'. invalid_models.target2: Accessor for field 'foreign_tgt' clashes with related field 'Target.target2_set'. Add a related_name argument to the definition for 'foreign_tgt'. invalid_models.target2: Accessor for field 'clashforeign_set' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'clashforeign_set'. invalid_models.target2: Accessor for field 'clashforeign_set' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'clashforeign_set'. invalid_models.target2: Accessor for field 'clashforeign_set' clashes with related field 'Target.target2_set'. Add a related_name argument to the definition for 'clashforeign_set'. invalid_models.target2: Accessor for m2m field 'm2m_tgt' clashes with related field 'Target.target2_set'. Add a related_name argument to the definition for 'm2m_tgt'. invalid_models.target2: Accessor for m2m field 'm2m_tgt' clashes with related field 'Target.target2_set'. Add a related_name argument to the definition for 'm2m_tgt'. invalid_models.target2: Accessor for m2m field 'm2m_tgt' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'm2m_tgt'. invalid_models.target2: Accessor for m2m field 'm2m_tgt' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'm2m_tgt'. invalid_models.target2: Accessor for m2m field 'm2m_tgt' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'm2m_tgt'. invalid_models.target2: Accessor for m2m field 'clashm2m_set' clashes with related field 'Target.target2_set'. Add a related_name argument to the definition for 'clashm2m_set'. invalid_models.target2: Accessor for m2m field 'clashm2m_set' clashes with related field 'Target.target2_set'. Add a related_name argument to the definition for 'clashm2m_set'. invalid_models.target2: Accessor for m2m field 'clashm2m_set' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'clashm2m_set'. invalid_models.target2: Accessor for m2m field 'clashm2m_set' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'clashm2m_set'. invalid_models.target2: Accessor for m2m field 'clashm2m_set' clashes with related m2m field 'Target.target2_set'. Add a related_name argument to the definition for 'clashm2m_set'. invalid_models.selfclashforeign: Accessor for field 'selfclashforeign_set' clashes with field 'SelfClashForeign.selfclashforeign_set'. Add a related_name argument to the definition for 'selfclashforeign_set'. invalid_models.selfclashforeign: Reverse query name for field 'selfclashforeign_set' clashes with field 'SelfClashForeign.selfclashforeign'. Add a related_name argument to the definition for 'selfclashforeign_set'. invalid_models.selfclashforeign: Accessor for field 'foreign_1' clashes with field 'SelfClashForeign.id'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.selfclashforeign: Reverse query name for field 'foreign_1' clashes with field 'SelfClashForeign.id'. Add a related_name argument to the definition for 'foreign_1'. invalid_models.selfclashforeign: Accessor for field 'foreign_2' clashes with field 'SelfClashForeign.src_safe'. Add a related_name argument to the definition for 'foreign_2'. invalid_models.selfclashforeign: Reverse query name for field 'foreign_2' clashes with field 'SelfClashForeign.src_safe'. Add a related_name argument to the definition for 'foreign_2'. invalid_models.selfclashm2m: Accessor for m2m field 'selfclashm2m_set' clashes with m2m field 'SelfClashM2M.selfclashm2m_set'. Add a related_name argument to the definition for 'selfclashm2m_set'. invalid_models.selfclashm2m: Reverse query name for m2m field 'selfclashm2m_set' clashes with field 'SelfClashM2M.selfclashm2m'. Add a related_name argument to the definition for 'selfclashm2m_set'. invalid_models.selfclashm2m: Accessor for m2m field 'selfclashm2m_set' clashes with related m2m field 'SelfClashM2M.selfclashm2m_set'. Add a related_name argument to the definition for 'selfclashm2m_set'. invalid_models.selfclashm2m: Accessor for m2m field 'm2m_1' clashes with field 'SelfClashM2M.id'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.selfclashm2m: Accessor for m2m field 'm2m_2' clashes with field 'SelfClashM2M.src_safe'. Add a related_name argument to the definition for 'm2m_2'. invalid_models.selfclashm2m: Reverse query name for m2m field 'm2m_1' clashes with field 'SelfClashM2M.id'. Add a related_name argument to the definition for 'm2m_1'. invalid_models.selfclashm2m: Reverse query name for m2m field 'm2m_2' clashes with field 'SelfClashM2M.src_safe'. Add a related_name argument to the definition for 'm2m_2'. invalid_models.selfclashm2m: Accessor for m2m field 'm2m_3' clashes with m2m field 'SelfClashM2M.selfclashm2m_set'. Add a related_name argument to the definition for 'm2m_3'. invalid_models.selfclashm2m: Accessor for m2m field 'm2m_3' clashes with related m2m field 'SelfClashM2M.selfclashm2m_set'. Add a related_name argument to the definition for 'm2m_3'. invalid_models.selfclashm2m: Accessor for m2m field 'm2m_3' clashes with related m2m field 'SelfClashM2M.selfclashm2m_set'. Add a related_name argument to the definition for 'm2m_3'. invalid_models.selfclashm2m: Accessor for m2m field 'm2m_4' clashes with m2m field 'SelfClashM2M.selfclashm2m_set'. Add a related_name argument to the definition for 'm2m_4'. invalid_models.selfclashm2m: Accessor for m2m field 'm2m_4' clashes with related m2m field 'SelfClashM2M.selfclashm2m_set'. Add a related_name argument to the definition for 'm2m_4'. invalid_models.selfclashm2m: Accessor for m2m field 'm2m_4' clashes with related m2m field 'SelfClashM2M.selfclashm2m_set'. Add a related_name argument to the definition for 'm2m_4'. invalid_models.selfclashm2m: Reverse query name for m2m field 'm2m_3' clashes with field 'SelfClashM2M.selfclashm2m'. Add a related_name argument to the definition for 'm2m_3'. invalid_models.selfclashm2m: Reverse query name for m2m field 'm2m_4' clashes with field 'SelfClashM2M.selfclashm2m'. Add a related_name argument to the definition for 'm2m_4'. invalid_models.missingrelations: 'rel1' has a relation with model Rel1, which has either not been installed or is abstract. invalid_models.missingrelations: 'rel2' has an m2m relation with model Rel2, which has either not been installed or is abstract. invalid_models.grouptwo: 'primary' is a manually-defined m2m relation through model Membership, which does not have foreign keys to Person and GroupTwo invalid_models.grouptwo: 'secondary' is a manually-defined m2m relation through model MembershipMissingFK, which does not have foreign keys to Group and GroupTwo invalid_models.missingmanualm2mmodel: 'missing_m2m' specifies an m2m relation through model MissingM2MModel, which has not been installed invalid_models.group: The model Group has two manually-defined m2m relations through the model Membership, which is not permitted. Please consider using an extra field on your intermediary model instead. invalid_models.group: Intermediary model RelationshipDoubleFK has more than one foreign key to Person, which is ambiguous and is not permitted. invalid_models.personselfrefm2m: Many-to-many fields with intermediate tables cannot be symmetrical. invalid_models.personselfrefm2m: Intermediary model RelationshipTripleFK has more than two foreign keys to PersonSelfRefM2M, which is ambiguous and is not permitted. invalid_models.personselfrefm2mexplicit: Many-to-many fields with intermediate tables cannot be symmetrical. invalid_models.abstractrelationmodel: 'fk1' has a relation with model AbstractModel, which has either not been installed or is abstract. invalid_models.abstractrelationmodel: 'fk2' has an m2m relation with model AbstractModel, which has either not been installed or is abstract. invalid_models.uniquem2m: ManyToManyFields cannot be unique. Remove the unique argument on 'unique_people'. invalid_models.nonuniquefktarget1: Field 'bad' under model 'FKTarget' must have a unique=True constraint. invalid_models.nonuniquefktarget2: Field 'bad' under model 'FKTarget' must have a unique=True constraint. invalid_models.nonexistingorderingwithsingleunderscore: "ordering" refers to "does_not_exist", a field that doesn't exist. invalid_models.articleattachment: Model 'UserTaggedObject' must have a GenericForeignKey in order to create a GenericRelation that points to it. """