序列化 RAW SQL 查询 Django

Question

希望你一切顺利。我需要序列化我的 RAW SQL 查询：

SELECT nn.*,nm.*FROM notifications_newsletter nn LEFT JOIN notifications_message nm ON nn.id=nm.newsletter_id_id ORDER by nm.status DESC

models.py

from django.db import models


class Newsletter(models.Model):
    start_datetime = models.DateTimeField()
    text = models.TextField(blank=True)
    filter = models.ForeignKey('Filter', null=True, on_delete=models.SET_NULL)
    end_datetime = models.DateTimeField()


class Message(models.Model):
    send_datetime = models.DateTimeField('%Y-%m-%d %H:%M:%S', auto_now=True)
    status = models.BooleanField(default=False)
    newsletter_id = models.ForeignKey('Newsletter', on_delete=models.CASCADE)
    client_id = models.ForeignKey('Client', on_delete=models.CASCADE)

views.py

from django.core.serializers import serialize
from django.http import HttpResponse

from .models import Newsletter


def some_view(request):
    sql = 'SELECT nn.*,nm.*FROM notifications_newsletter nn ' \
          'LEFT JOIN notifications_message nm ' \
          'ON nn.id=nm.newsletter_id_id ORDER by nm.status DESC'
    qs = Newsletter.objects.raw(sql)
    qs_json = serialize('json', qs)
    return HttpResponse(qs_json, content_type='application/json')

如果我使用 serializers.serialize() 响应中不存在所有连接数据（消息 table）。但是，如果 print(qs.columns) 列 send_datetime、状态等 将被打印。

回复：

[
    {
        "model": "notifications.newsletter",
        "pk": 42,
        "fields": {
            "start_datetime": "2022-01-21T21:56:09Z",
            "text": "This is test message for 900 operator code.",
            "filter": 1,
            "end_datetime": "2022-01-21T18:00:00Z"
        }
    },
]

我需要这样的东西：

[
    {
        "model": "notifications.newsletter",
        "pk": 43,
        "fields": {
            "start_datetime": "2022-01-21T22:03:26Z",
            "text": "This is test message for 904 operator code.",
            "filter": 2,
            "end_datetime": "2022-01-21T18:00:00Z",
            "messages": [
                {
                    "send_datetime": "2022-01-21T22:03:26Z",
                    "status": 0,
                    "newsletter_id": 43,
                    "client_id": 1
                },
            ]
        }
    },
]

是否可以正常序列化？

Answer 1

您可以使用 Django REST Framework 中的嵌套模型序列化程序来达到您的目的：

from rest_framework import serializers

class MessageSerializer(serializers.ModelSerializer):
    class Meta:
        model = Message
        fields = "__all__"

class NewsletterSerializer(serializers.ModelSerializer):
    messages = MessageSerializer(many=True)

    class Meta:
        model = Newsletter
        fields = "__all__"

并在您的视图中使用 NewsletterSerializer：

from django.core.serializers import serialize
from django.http import HttpResponse

from .models import Newsletter


def some_view(request):
    sql = 'SELECT nn.*,nm.*FROM notifications_newsletter nn ' \
          'LEFT JOIN notifications_message nm ' \
          'ON nn.id=nm.newsletter_id_id ORDER by nm.status DESC'
    qs = Newsletter.objects.raw(sql)
    qs_json = NewsletterSerializer(qs, many=True).data
    return HttpResponse(qs_json, content_type='application/json')

您还必须对代码进行一些其他更改：

您必须将字段 newsletter_id、client_id 分别重命名为 newsletter、client。您可以阅读更多相关信息 here。
您必须在 Message 模型的 newsletter 外键中指定 related_name。像这样将其设置为 messages：

newsletter = models.ForeignKey('Newsletter', on_delete=models.CASCADE, related_name='messages')

您必须重命名您的 filter 字段，因为它是保留关键字。

序列化 RAW SQL 查询 Django

Serializing RAW SQL query Django

python

django

orm

django-rest-framework