django override delete cascade for one time











up vote
2
down vote

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2












Is there an option for to make sure that a model instance does not have any related objects?
i.e, if the Person object has any related objects, I want this line



person.delete()


to raise an error.



And I don't want to modify on_delete=models.CASCADE for every foreign key. I need this protection only here, for any other case in my application (like django admin site) I do prefer the cascading behavior.










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  • 1




    Do you try to overrife delete method from your model? check for your fk and others inside this method and call super(...).delete() to delete your model
    – Bast
    Nov 8 at 9:42










  • I didn't override the delete method
    – user3599803
    Nov 8 at 12:52

















up vote
2
down vote

favorite
2












Is there an option for to make sure that a model instance does not have any related objects?
i.e, if the Person object has any related objects, I want this line



person.delete()


to raise an error.



And I don't want to modify on_delete=models.CASCADE for every foreign key. I need this protection only here, for any other case in my application (like django admin site) I do prefer the cascading behavior.










share|improve this question


















  • 1




    Do you try to overrife delete method from your model? check for your fk and others inside this method and call super(...).delete() to delete your model
    – Bast
    Nov 8 at 9:42










  • I didn't override the delete method
    – user3599803
    Nov 8 at 12:52















up vote
2
down vote

favorite
2









up vote
2
down vote

favorite
2






2





Is there an option for to make sure that a model instance does not have any related objects?
i.e, if the Person object has any related objects, I want this line



person.delete()


to raise an error.



And I don't want to modify on_delete=models.CASCADE for every foreign key. I need this protection only here, for any other case in my application (like django admin site) I do prefer the cascading behavior.










share|improve this question













Is there an option for to make sure that a model instance does not have any related objects?
i.e, if the Person object has any related objects, I want this line



person.delete()


to raise an error.



And I don't want to modify on_delete=models.CASCADE for every foreign key. I need this protection only here, for any other case in my application (like django admin site) I do prefer the cascading behavior.







python django django-models django-queryset






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share|improve this question










asked Nov 8 at 9:35









user3599803

77831337




77831337








  • 1




    Do you try to overrife delete method from your model? check for your fk and others inside this method and call super(...).delete() to delete your model
    – Bast
    Nov 8 at 9:42










  • I didn't override the delete method
    – user3599803
    Nov 8 at 12:52
















  • 1




    Do you try to overrife delete method from your model? check for your fk and others inside this method and call super(...).delete() to delete your model
    – Bast
    Nov 8 at 9:42










  • I didn't override the delete method
    – user3599803
    Nov 8 at 12:52










1




1




Do you try to overrife delete method from your model? check for your fk and others inside this method and call super(...).delete() to delete your model
– Bast
Nov 8 at 9:42




Do you try to overrife delete method from your model? check for your fk and others inside this method and call super(...).delete() to delete your model
– Bast
Nov 8 at 9:42












I didn't override the delete method
– user3599803
Nov 8 at 12:52






I didn't override the delete method
– user3599803
Nov 8 at 12:52














1 Answer
1






active

oldest

votes

















up vote
1
down vote



accepted










Does this correspond to what you want?



has_related = False
for field in person.__class__._meta.get_fields():
if field.is_relation:
field_name = field.get_accessor_name()
model_field = getattr(person, field_name)
if not isinstance(model_field, models.Model) and model_field.all():
has_related = True
break

if not has_related:
person.delete()





share|improve this answer























  • Thanks, why the use of get_cache_name() for field objects? I'm getting an AttributeError
    – user3599803
    Nov 8 at 12:52










  • I updated my post with get_accessor_name() instead of get_cache_name(). We use this method to get the XXX_set (or else if modified) name of the related field. Where do you get your AttributeError ?
    – mistiru
    Nov 8 at 13:49











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
1
down vote



accepted










Does this correspond to what you want?



has_related = False
for field in person.__class__._meta.get_fields():
if field.is_relation:
field_name = field.get_accessor_name()
model_field = getattr(person, field_name)
if not isinstance(model_field, models.Model) and model_field.all():
has_related = True
break

if not has_related:
person.delete()





share|improve this answer























  • Thanks, why the use of get_cache_name() for field objects? I'm getting an AttributeError
    – user3599803
    Nov 8 at 12:52










  • I updated my post with get_accessor_name() instead of get_cache_name(). We use this method to get the XXX_set (or else if modified) name of the related field. Where do you get your AttributeError ?
    – mistiru
    Nov 8 at 13:49















up vote
1
down vote



accepted










Does this correspond to what you want?



has_related = False
for field in person.__class__._meta.get_fields():
if field.is_relation:
field_name = field.get_accessor_name()
model_field = getattr(person, field_name)
if not isinstance(model_field, models.Model) and model_field.all():
has_related = True
break

if not has_related:
person.delete()





share|improve this answer























  • Thanks, why the use of get_cache_name() for field objects? I'm getting an AttributeError
    – user3599803
    Nov 8 at 12:52










  • I updated my post with get_accessor_name() instead of get_cache_name(). We use this method to get the XXX_set (or else if modified) name of the related field. Where do you get your AttributeError ?
    – mistiru
    Nov 8 at 13:49













up vote
1
down vote



accepted







up vote
1
down vote



accepted






Does this correspond to what you want?



has_related = False
for field in person.__class__._meta.get_fields():
if field.is_relation:
field_name = field.get_accessor_name()
model_field = getattr(person, field_name)
if not isinstance(model_field, models.Model) and model_field.all():
has_related = True
break

if not has_related:
person.delete()





share|improve this answer














Does this correspond to what you want?



has_related = False
for field in person.__class__._meta.get_fields():
if field.is_relation:
field_name = field.get_accessor_name()
model_field = getattr(person, field_name)
if not isinstance(model_field, models.Model) and model_field.all():
has_related = True
break

if not has_related:
person.delete()






share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 8 at 13:47

























answered Nov 8 at 11:06









mistiru

39512




39512












  • Thanks, why the use of get_cache_name() for field objects? I'm getting an AttributeError
    – user3599803
    Nov 8 at 12:52










  • I updated my post with get_accessor_name() instead of get_cache_name(). We use this method to get the XXX_set (or else if modified) name of the related field. Where do you get your AttributeError ?
    – mistiru
    Nov 8 at 13:49


















  • Thanks, why the use of get_cache_name() for field objects? I'm getting an AttributeError
    – user3599803
    Nov 8 at 12:52










  • I updated my post with get_accessor_name() instead of get_cache_name(). We use this method to get the XXX_set (or else if modified) name of the related field. Where do you get your AttributeError ?
    – mistiru
    Nov 8 at 13:49
















Thanks, why the use of get_cache_name() for field objects? I'm getting an AttributeError
– user3599803
Nov 8 at 12:52




Thanks, why the use of get_cache_name() for field objects? I'm getting an AttributeError
– user3599803
Nov 8 at 12:52












I updated my post with get_accessor_name() instead of get_cache_name(). We use this method to get the XXX_set (or else if modified) name of the related field. Where do you get your AttributeError ?
– mistiru
Nov 8 at 13:49




I updated my post with get_accessor_name() instead of get_cache_name(). We use this method to get the XXX_set (or else if modified) name of the related field. Where do you get your AttributeError ?
– mistiru
Nov 8 at 13:49


















 

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