在一个PUT/PATCH中更新多个数据库表

Question

我正在用rest-framework-mongoengine编写一个django-rest-framework后端。到目前为止，我有两种类型的架构 - 用户和设备（Box）。来源如下：

models.py：

from __future__ import unicode_literals 

import datetime 
from mongoengine import Document, connect, EmbeddedDocument, fields, DynamicDocument 
from django.db import models 

# Create your models here. 
from mongoengine import signals 

connect('yourdb', alias='default') 

class GPS(EmbeddedDocument): 
    lat = fields.FloatField(null=False, required=True) 
    lon = fields.FloatField(null=False, required=True) 


class PPM(EmbeddedDocument): 
    time = fields.DateTimeField(default=datetime.datetime.now()) 
    value = fields.IntField(null=False, required=True) 

    @classmethod 
    def pre_save(cls, sender, document, **kwargs): 
     document.time = datetime.datetime.now() 


signals.pre_save.connect(PPM.pre_save, sender=PPM) 

class BuyHistory(EmbeddedDocument): 
    time = fields.DateTimeField(default=datetime.datetime.now()) 
    boxid = fields.StringField(max_length=128, null=False, required=True) 
    username = fields.StringField(max_length=128, null=False, required=True) 
    product = fields.StringField(max_length=128, null=False, required=True) 
    amount = fields.IntField() 

    @classmethod 
    def pre_save(cls, sender, document, **kwargs): 
     document.time = datetime.datetime.now() 


signals.pre_save.connect(BuyHistory.pre_save, sender=BuyHistory) 

class RecycleHistory(EmbeddedDocument): 
    time = fields.DateTimeField(default=datetime.datetime.now()) 
    boxid = fields.StringField(max_length=128, null=False, required=True) 
    username = fields.StringField(max_length=128, null=False, required=True) 
    amount = fields.IntField() 

    @classmethod 
    def pre_save(cls, sender, document, **kwargs): 
     document.time = datetime.datetime.now() 


signals.pre_save.connect(RecycleHistory.pre_save, sender=RecycleHistory) 

class Box(Document): 
    boxid = fields.StringField(max_length=128, null=False, required=True) 
    gps = fields.EmbeddedDocumentField(GPS, required=True) 
    buy_history = fields.EmbeddedDocumentListField(BuyHistory, default='[]') 
    recycle_history = fields.EmbeddedDocumentListField(RecycleHistory, default='[]') 
    ppm_history = fields.EmbeddedDocumentListField(PPM, default='[]') 

class User(Document): 
    username = fields.StringField(max_length=128, null=False, required=True) 
    rfid = fields.StringField(max_length=32, null=False, required=True) 
    buy_history = fields.EmbeddedDocumentListField(BuyHistory) 
    recycle_history = fields.EmbeddedDocumentListField(RecycleHistory) 

serializers.py：

from rest_framework_mongoengine import serializers 
from models import User, BuyHistory, Box, RecycleHistory, PPM 

class UserSerializer(serializers.DocumentSerializer): 
    class Meta: 
     model = User 
     fields = ('username', 'rfid', 'buy_history', 'recycle_history') 


class PPMSerializer(serializers.DocumentSerializer): 
    class Meta: 
     model = PPM 
     fields = ('time', 'value') 


class BuyHistorySerializer(serializers.EmbeddedDocumentSerializer): 
    class Meta: 
     model = BuyHistory 
     fields = ('time', 'boxid', 'username', 'product', 'amount') 


class RecycleHistorySerializer(serializers.EmbeddedDocumentSerializer): 
    class Meta: 
     model = RecycleHistory 
     fields = ('time', 'boxid', 'username', 'product', 'amount') 


class BoxSerializer(serializers.DocumentSerializer): 
    class Meta: 
     model = Box 
     fields = ('id', 'boxid', 'gps', 'buy_history', 'recycle_history', 'ppm_history') 

    def update(self, instance, validated_data): 
     buy = validated_data.pop('buy_history') 
     recycle = validated_data.pop('recycle_history') 
     ppm = validated_data.pop('ppm_history') 
     updated_instance = super(BoxSerializer, self).update(instance, validated_data) 

     for buy_data in buy: 
      updated_instance.buy_history.append(BuyHistory(**buy_data)) 
     for recycle_data in recycle: 
      updated_instance.recycle_history.append(RecycleHistory(**recycle_data)) 
     for ppm_data in ppm: 
      updated_instance.ppm_history.append(PPM(**ppm_data)) 
     updated_instance.save() 
     return updated_instance 

我的目标是更新用户的buy_history和recycle_history更新Box对象时。我该怎么做？

Answer 1

好吧，我已经找到了解决办法，显然这是超级简单，但如果有人有类似的困惑，这里的答案：

只是这是在嵌套对象设置这样username得到user。

for buy_data in buy: 
    buy_history_s = BuyHistory(**buy_data) 
    try: 
     user = User.objects.get(username=buy_history_s.username) 
    except errors.DoesNotExist: 
     raise exceptions.AuthenticationFailed() 
    if buy_history_s.time is None: 
     buy_history_s.time = datetime.datetime.now() 
    updated_instance.buy_history.append(buy_history_s) 
    user.buy_history.append(buy_history_s) 
    user.save() 

干杯