MongoEngine：EmbeddedDocumentListField() 和 ListField(EmbeddedDocumentField()) 之间的区别？

Question

标题。这两个语句是做同样的事情，还是我在这里遗漏了什么？

cars = db.EmbeddedDocumentListField(Car, default= [])

对

cars = db.ListField(db.EmbeddedDocumentField(Car), default=[])

Answer 1

EmbeddedDocumentListField 支持在返回的嵌入文档列表上查询 count()、filter()、delete()、create() 等操作。因此，使用 EmbeddedDocumentListField() 而不是 List(EmbeddedDocumentField()) 会更有益。

更多详情和方法列表请参考：

http://docs.mongoengine.org/apireference.html#embedded-document-querying

== 编辑：更多细节 ==

下面是一个使用 EmbeddedDocumentListField 方法的示例，展示了如何将 EmbeddedDocument 添加到 EmbeddedDocumentListField 主文档模型下 2 层：

model1_obj.model2_list.get(model2_id_field=model2_id).model3_list.create(**model3_data)

或

model1_obj.model2_list.filter(model2_id_field=model2_id).first().model3_list.create(**model3_data)

以下是与此代码段相关的模型和视图类：

models.py:

from mongoengine import *

class Model3(EmbeddedDocument):
    field1 = StringField()
    field2 = StringField()
    field3 = StringField()

class Model2(EmbeddedDocument):
    # other fields
    model2_id_field = # Some field
    model3_list = EmbeddedDocumentListField(Model3)

class Model1(Document):
    # other fields
    model2_list = EmbeddedDocumentListField(Model2)

views.py: (Implements patch method using Django rest framework)

class Model1AddModel3(APIView):
    def get_object(self, id):
        return Model1.objects.get(pk=id)

    def patch(self, request, id, format=None):
        model1_obj = self.get_object(id)
        #
        # Validate request.data here
        # Extract model2 identifier and model3 data from request.data
        # e.g.:
        # model2_id = request.data['model2id']
        # model3_data = {'field1': 'a', 'field2': 'a', 'field3': 'a', }
        #
        model1_obj.model2_list.get(model2_id_field=model2_id).model3_list.create(**model3_data)
        #
        # You can also use:
        # model1_obj.model2_list.filter(model2_id_field=model2_id).first().model3_list.create(**model3_data)
        #
        model1_obj.save()
        return Response(some_data, status=status.HTTP_201_CREATED)

MongoEngine：EmbeddedDocumentListField() 和 ListField(EmbeddedDocumentField()) 之间的区别？

MongoEngine: difference between EmbeddedDocumentListField() and ListField(EmbeddedDocumentField())?

python

mongoengine