我目前是一名学生,正在尝试使用 python/django 和 React 创建一个完整的堆栈 Web 应用程序。在构建后端时,我遇到了一个问题,即在发布包含关联的对象时,关联的 id 在响应负载和数据库之间丢失。我知道状态正在按其应有的方式更新,并且可以毫无问题地创建在后端不使用关联的其他对象。我认为我的错误一定是在我制作的模型或序列化器中的某个地方,但到目前为止我还没有找到它。
500 错误消息:
Integrity error at "api/v1/event"
null value in column "timeline_id" violates not-null constraint
DETAIL: failing row contains (index_id, junk_data, junk_data, 1, null)
我的模型:
from django.db import models
class Timeline(models.Model):
name = models.CharField(max_length=50, default='n/a')
def __str__(self):
return self.name
class Event(models.Model):
name = models.CharField(max_length=25, default='n/a')
description = models.CharField(max_length=150, default='n/a')
coordinate = models.IntegerField(default=0)
timeline = models.ForeignKey(Timeline, on_delete=models.CASCADE, related_name="events")
def __str__(self):
return self.name
class Note(models.Model):
article = models.TextField(default='n/a')
event = models.ForeignKey(Event, on_delete=models.CASCADE, related_name='notes')
# event = models.ManyToManyField(Event)
def __str__(self):
return self.article
我的观点:
from rest_framework import viewsets
from .serializers import TimelineSerializer, EventSerializer, NoteSerializer
from .models import Timeline, Event, Note
class TimelineView(viewsets.ModelViewSet):
queryset = Timeline.objects.all()
serializer_class = TimelineSerializer
class EventView(viewsets.ModelViewSet):
queryset = Event.objects.all()
serializer_class = EventSerializer
class NoteView(viewsets.ModelViewSet):
queryset = Note.objects.all()
serializer_class = NoteSerializer
我的序列化器:
from rest_framework import serializers
from .models import Timeline, Note, Event
class NoteSerializer(serializers.ModelSerializer):
class Meta:
model = Note
fields = ('id', 'title', 'article')
class EventSerializer(serializers.ModelSerializer):
notes = NoteSerializer(many=True, read_only=True)
class Meta:
model = Event
fields = ('id', 'name', 'description', 'coordinate', 'notes')
class TimelineSerializer(serializers.ModelSerializer):
events = EventSerializer(many=True, read_only=True)
class Meta:
model = Timeline
fields = ('id', 'name', 'events')
链接到 github 存储库: https://github.com/dantehollo/world_builder_site
我在 Linux (ubuntu 18.04.3) 上使用 python 3.6.8
我尝试尽可能具体和简短。如果缺少什么,请告诉我,我会在看到请求后立即发布。非常感谢任何关于这是什么、为什么会发生以及如何避免再次发生这种情况的帮助,谢谢。
最佳答案
根据您的 Event
模型,timeline
属性(也是外键)是必需的,并且不能为空。并且您忘记将此时间线
添加到EventSerializer的字段中:
class EventSerializer(serializers.ModelSerializer):
notes = NoteSerializer(many=True, read_only=True)
class Meta:
model = Event
fields = ('id', 'name', 'description', 'coordinate', 'notes', 'timeline')
现在,如果您不在请求中发送timeline
,DRF 将给出 ValidationError,表明您必须将其包含在内。
关于python - 500错误: null value in column "timeline_id" violates not-null constraint,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/59077537/