update multiple django id's at once

Solution 1:

Use __in to query for all the items at once, instead of looping over the ids

ids = request.POST.getlist("id")
qs = fp.objects.filter(id__in=ids)

You can use the queryset's .update method to update all items in the queryset at once.

P_350 = request.POST["P_350"]
P_450 = request.POST["P_450"]

updates = {}
if len(P_350) > 1:
    updates['P_350'] = P_350
if len(P_450) > 1:
    updates['P_450'] = P_450

if updates:
    qs.update(**updates)