Why am I getting UNIQUE constraint failed: offers_offer.currencyId_id?

Question

Django

I filter xml model and save it like this

try:
    # check model
    offer = Offer.objects.get(id = lxml_id)

    currencyId = host_ip.find('currencyId').text
    print(currencyId)
    currency = Currency.objects.get(name = currencyId)
    print(offer.currencyId)
    if not offer.currencyId == currencyId:
      offer.currencyId = currency
      save_model = True
    
    if save_model:
      offer.save()
      print('save 3')

But I get UNIQUE constraint failed: offers_offer.currencyId_id
How can I fix this?

Answer 1

The database already has an offer record with currencyId equal to currency