django - 在 Django 更新后,Django 插入中的重复键违规
问题描述
首先我更新我的模型实例,之后我尝试插入一个新数据但显示
"IntegrityError('重复键值违反了唯一约束 "RFIDActivation_ActivationId_key"\nDETAIL: Key ("ActivationId")=(6de9ed9a) 已经存在。\n',)"
模型.py
class RFIDActivation(models.Model):
RFIDActivationId = models.AutoField(primary_key=True, db_column='RFIDActivationId')
Device = models.ForeignKey(Device, on_delete=models.CASCADE, db_column='DeviceId')
Employee = models.ForeignKey(Employee, on_delete=models.CASCADE, db_column='EmployeeId')
ActivationId = models.CharField(max_length=10, unique=True, default=uuid4().hex[:8])
ActivationStatus = models.CharField(max_length=1)default=None)
class Meta:
db_table = "RFIDActivation"
我的序列化程序.py
class RFIDActivationSerializer(serializers.ModelSerializer):
class Meta:
model = RFIDActivation
fields = '__all__'
视图.py
@api_view(["POST"])
@permission_classes([IsAuthenticated])
def rfid_activation_initial(request):
RFIDActivation.objects.filter(Employee=request.POST.get("Employee")).update(
ActivationStatus='2',
ActivationMessage='Abort'
)
rfid_activation = {
'Employee': request.POST.get("Employee"),
'Device': request.POST.get("Device"),
'ActivationStatus': "0",
'ActivationMessage': "RFID Activation Initiated"
}
rfid_serializer = RFIDActivationSerializer(data=rfid_activation)
if rfid_serializer.is_valid():
rfid_serializer.save()
但 rfid_serializer.save() 显示异常异常
以前的 ActivationId 用于保存新数据。ActivationId 是唯一的并且是自动生成的。我该如何解决这个问题。错误显示在更新查询后尝试插入
view.py 用于工作正常的代码仅插入。
@api_view(["POST"])
@permission_classes([IsAuthenticated])
def rfid_data_add(request):
rfid_activation = {
'Employee': request.POST.get("Employee"),
'Device': request.POST.get("Device"),
'ActivationStatus': "0",
'ActivationMessage': "RFID Activation Initiated"
}
rfid_serializer = RFIDActivationSerializer(data=rfid_activation)
if rfid_serializer.is_valid():
rfid_serializer.save()
解决方案
在 restframework 中,serializer.save()
根据创建和更新有不同的行为。如果将实例传递给序列化器,它将更新对象,否则,它将创建一个新对象
@api_view(['POST', 'PUT'])
def rfid_data(request, pk):
"""
Update or delete a rfid data.
"""
rfid_activation = {
...
}
if request.method == 'POST':
rfid_serializer = RFIDActivationSerializer(data=rfid_activation)
if rfid_serializer.is_valid():
rfid_serializer.save()
return Response(rfid_serializer.data,status=status.HTTP_201_CREATED)
return return Response(rfid_serializer.data, status=status.HTTP_400_BAD_REQUEST)
# PUT is used for object update
elif request.method == 'PUT':
rfid = RFIDActivation.objects.get(pk=pk)
# pass instance to your serializer
# pass partial=True to allow partial updates
rfid_serializer = RFIDActivationSerializer(instance=rfid, data=rfid_activation, partial=True)
if rfid_serializer.is_valid():
rfid_serializer.save()
return Response(rfid_serializer.data)
return Response(rfid_serializer.errors, status=status.HTTP_400_BAD_REQUEST)
更新
default
计算为import time
,在您的情况下,您的默认值activation_id
计算一次,并且对于后续实例永远不会更改。您必须定义一个函数,因此每次创建对象时都会更新默认可调用对象,请在此处阅读更多信息
def activation_id_generator(self):
return uuid4().hex[:8]
# then in your class
class RFIDActivation(models.Model):
...
ActivationId = models.CharField(max_length=10, unique=True, default=activation_id_generator)
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