Question

我观察到document[field]返回{}的mongo文档，但是我似乎无法创建这样的文档。示例：

import mongoengine

mongoengine.connect('FOO', host='localhost', port=27017)

class Foo(mongoengine.Document):
    some_dict = mongoengine.DictField()
    message = mongoengine.StringField()

ID = '59b97ec7c5d65e0c4740b886'
foo = Foo()
foo.some_dict = {}
foo.id = ID
foo.save()

但是当我查询记录时，some_dict不在字段中，因此最后一行会引发错误：

import pymongo
CON = pymongo.MongoClient('localhost',27017)
x = CON.FOO.foo.find_one()
assert str(x['_id']) == ID
assert 'some_dict' in x.keys()

Answer 1

一个明显的解决方法是在文档创建后对其进行更新，但是感觉太过分了。我希望mongoengine可以让直接操作变得容易：

import mongoengine
import pymongo
CON = pymongo.MongoClient('localhost',27017)
CON.Foo.foo.remove()

mongoengine.connect('FOO', host='localhost', port=27017)

class Foo(mongoengine.Document):
    some_dict = mongoengine.DictField()
    some_list = mongoengine.ListField()

ID = '59b97ec7c5d65e0c4740b886'
foo = Foo()
foo.id = ID
foo.save()

from bson.objectid import ObjectId
CON.FOO.foo.update_one({'_id': ObjectId(ID)},
                       {'$set': {'some_dict': {}}}, upsert=False)

x = CON.FOO.foo.find_one()
assert str(x['_id']) == ID
assert 'some_dict' in x.keys()

使用mongoengine写一个空的dict字段

1 个答案: