Filter Objects If All Its Foreignkeys Are In A Dictionary
what i need is to allow users to access list of Parent objects by filtering their related objects `Kid' We have a dictionary that has a 100 kid. and parents that have about 5 kids
Solution 1:
Here is what I would do if I understood your question correctly.
def index(request):
patterns = [
{'name': 'samy', 'age__lt': 15, 'city': 'paris'},
{'name': 'sally', 'age__gt': 20, 'city': 'london'}
]
filter_q = reduce(operator.or_, map(lambda p: Q(**p), patterns))
qs = Kid.objects.filter(filter_q).values_list('id', 'family_id')
family_ids = set()
child_ids = list()
for child_id, family_id in qs:
family_ids.add(family_id)
child_ids.append(child_id)
# At this point we have the complete list of matching Kid(s) in child_ids
# . . . and we have a list of all family IDs in which those Kid(s) exist
# Now we look for incomplete families,
# i.e., families that were part of the first query,
# but have Kid(s) that are not in our complete list
# of matching kids.
incomplete_family_ids = set(Kid.objects.exclude(id__in=child_ids).filter(family_id__in=family_ids).values_list('family_id', flat=True).distinct())
# Now we find the set complement to make life on the database a little easier.
complete_family_ids = family_ids - incomplete_family_ids
parents = Parent.objects.filter(id__in=complete_family_ids)
template = 'index.html'
context = {'parents': parents}
return render(request, template, context)
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