Django on_delete=models.CASCADE 在使用相關名稱時不起作用

Question

我有一個名為 Proposal 的 model ，它通過兩個不同的字段與 model 客戶相關。 我希望如果任何相關用戶被刪除，提案也將被刪除。 但是， on_delete=models.CASCADE 沒有實現這一點。 我想我可以使用信號來觸發這種行為，但我想知道是否有更好的方法讓它在 Django 4.0 中工作。

class Proposal(models.Model):

    # foreign keys
    created_by_customer = models.ForeignKey(Customer, blank=False, on_delete=models.CASCADE)
    accepted_by_customer = models.ForeignKey(Customer, blank=True, null=True, on_delete=models.CASCADE, related_name='accepted_by_customer')

這是我對 Pytest 的測試：

@pytest.mark.django_db
def test_delete_proposal_from_created_by_customer():  
    """ Deleting customer that created the proposal must delete proposal """

    created_proposal = random_proposal()
    buyer = random_customer()
    created_proposal.created_by_customer = buyer
    created_proposal.created_by_customer.delete()

Answer 1

發現了問題。 測試是錯誤的。 在修改外鍵以應用更改時，您需要保存當前 model 和相關 model 。

@pytest.mark.django_db
def test_delete_proposal_from_created_by_customer():
    """ Deleting customer that created the proposal must delete proposal """

    created_proposal = random_proposal()
    buyer = random_customer()
    created_proposal.created_by_customer = buyer
    created_proposal.save()  # <----------
    created_proposal.created_by_customer.save()  # <----------
    created_proposal.created_by_customer.delete()

    assert True if Proposal.objects.all().count() == 0 else False