When I delete the model, How can I delete the inlines data and the uploaded file

Question

models.py

    class Issue(models.Model):
        issueId = models.AutoField(primary_key=True)
        title = models.CharField(max_length = 20)
        year = models.IntegerField()
        issueDate = models.DateField()

    class Preview(models.Model):
        issueId = models.ForeignKey(Issue);
        previewPath = models.FileField(upload_to='./upload/magazine_sample')

admin.py

    class PreviewInline(object):
        model = Preview
        extra = 1
        style = 'accordion'
        max_num = 1

    class IssueAdmin(object):
        list_display = ('title',)
        inlines = [PreviewInline]

    admin.site.register(Issue, IssueAdmin)

How can I delete the preview and the uploaded file when I delete the Issue model? Can anyone help me please?

Marcio Cruz · Accepted Answer · 2013-05-21T13:12:00.117

1

Are you sure the Issue is not being deleted? The defaul behavior for the ForeignKey is to cascade the deletion:

ForeignKey.on_delete When an object referenced by a ForeignKey is deleted, Django by default emulates the behavior of the SQL constraint ON DELETE CASCADE and also deletes the object containing the ForeignKey. This behavior can be overridden by specifying the on_delete argument.

Are you using sqlite3? I'm not sure it has cascading enabled by default.

To delete the image, you might want to use the pre_delete signal:

from django.db.models.signals import pre_save
from django.dispatch import receiver
from myapp.models import Preview

@receiver(pre_delete, sender=Preview)
def delete_image(sender, instance, using):
    # delete the image -> instance.previewPath

More info on signals: https://docs.djangoproject.com/en/dev/ref/signals/#django.db.models.signals.pre_delete https://docs.djangoproject.com/en/dev/topics/signals/

edited May 21 '13 at 13:12

answered May 17 '13 at 13:06

Marcio Cruz

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the issue and preview are all delete, and i want to delete the upload file – Bill_Xiong May 20 '13 at 04:44
To delete the image, you might want to use the post_delete signal – Marcio Cruz May 20 '13 at 12:56
i'm a newer in django's world. how to use post_delete signal? – Bill_Xiong May 21 '13 at 01:41
Its simple, all you need to know is in the docs: https://docs.djangoproject.com/en/dev/topics/signals/ . Think of signals as events; you register them and they get called later. – Marcio Cruz May 21 '13 at 13:05
I have updated the answer, check the example. Note that I changed from post_delete to pre_delete. – Marcio Cruz May 21 '13 at 13:12

When I delete the model, How can I delete the inlines data and the uploaded file

1 Answers1