python - UpdateOrCreate 建立一对多关系

Question

已更新

我正在尝试在父表上应用update_or_create方法。然后在 child table 上。但是，当 update_or_create 方法在子级上运行时，会返回此错误...

save() prohibited to prevent data loss due to unsaved related object 'atom_presance'.

看起来子进程不知道父进程的update_or_create并且无法获取foreign_key。

for i, fee in enumerate(fees):
   for j, item in enumerate(fee):
      projects = AtomPresance() #parent
      advertisements = Advertisements() #child

      project_name = {'project_name': item["title"]}

      kind = item["kind"]
      removed_price = {'removed_price': item[kind], "atom_presance":projects} #sending FOREIGN_KEY also

      obj, created = AtomPresance.objects.update_or_create(project_name=item["title"], defaults=project_name)
      obj, created = Advertisements.objects.update_or_create(saved_date=date, defaults=removed_price)

在这种情况下，在父级和子级上使用 update_or_create 的最佳方法是什么。

Answer 1

当您在默认值中使用update_or_create第二种方法将removed_price分配为第一次创建后放置的字典时，我收到错误AtomPresance 对象并在 removed_price 字典的 atom_presance=obj 中分配键值

you have must pass the reference of parentmodel in childmodel creation replace below code with your code

for i, fee in enumerate(fees):
   for j, item in enumerate(fee):
      project_name = {'project_name': item["title"]}

      kind = item["kind"]

      obj, created = AtomPresance.objects.update_or_create(project_name=item["title"], defaults=project_name)

      removed_price = {'removed_price': item[kind], "atom_presance":obj} #here change you need to assign the created obj that we create in above line 

      obj, created = Advertisements.objects.update_or_create(saved_date=date, defaults=removed_price)