Question

Django Rest Framework提供了有关如何实现批量更新的示例。该示例显示更新方法处理更新，创建和销毁实例。我无法理解的是新数据如何具有'id'，因为我认为一旦将对象保存到数据库就会创建id / pk。根据我的理解，当新实例在validated_data中时，第二行应该失败，因为它们没有id。

示例

class BookListSerializer(serializers.ListSerializer):
def update(self, instance, validated_data):
    book_mapping = {book.id: book for book in instance}
    data_mapping = {item['id']: item for item in validated_data} # --> shouldn't this fail if new items are in validated data?

    # Perform creations and updates.
    ret = []
    for book_id, data in data_mapping.items():
        book = book_mapping.get(book_id, None)
        if book is None:
            ret.append(self.child.create(data))
        else:
            ret.append(self.child.update(book, data))

    # Perform deletions.
    for book_id, book in book_mapping.items():
        if book_id not in data_mapping:
            book.delete()

    return ret

Link to the example in Django Rest Framework docs

Answer 1

我认为该示例需要设置id。您需要一个不同的算法来处理没有id

的项目创建

批量更新/创建一个请求

1 个答案: