The main issue here is that there are two types of batch deletes in Django:
1. You can query for the models you want to delete, loop through the queryset, and delete them each individually. Your custom delete methods (if any) will get called, and you'll get pre_delete and post_delete signals. That involves a lot of database communication, though. 2. A far more efficient method is to send a single delete command, and let the database do all the hard work on its end. This is what happens when you call delete() on a queryset. Of course, since all the important stuff happens on the database server, Django never hears about any of it. No custom delete methods get called, and no signals get sent. The documentation[1] says: 'When Django deletes an object, it emulates the behavior of the SQL constraint ON DELETE CASCADE — in other words, any objects which had foreign keys pointing at the object to be deleted will be deleted along with it.' It isn't very clear from that sentence which of the two methods Django uses to delete those child records, but looking at the code, it seems to be method #2. Since it's using the more-efficient batch delete, no custom delete methods are being called, no signals are being sent, which is exactly the problem you're having. The solution is to override the delete method (or respond to the pre_delete signal), on your *parent* model, in this case 'Participant'. That way, when you delete the Participant, you can delete all related Data records by hand. [1] http://www.djangoproject.com/documentation/db-api/#deleting-objects On Jun 17, 6:26 am, Daniel Austria <[EMAIL PROTECTED]> wrote: > Cool! > > Thank you very much for your response..... i ll use signals! > > regards > Dan --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
