Django 如何为联接模型编写序列化程序？

我已使用以下查询在两个表上应用了join

视图.PY

class performance(viewsets.ModelViewSet):

    queryset = Leads.objects.select_related('channelId'
        ).values("channelId__channelName").annotate(tcount=Count('channelId'))

    serializer_class = teamwise_lead_performance_serializer

class channel_serializer(serializers.ModelSerializer):
    class Meta:
        model = Channels
        fields = ['channelName']


class performance_serializer(serializers.ModelSerializer):
    tcount = serializers.IntegerField()
    channel = channel_serializer(many=True, read_only=True)

    class Meta:
        model = Leads
        fields = ['tcount', 'channel']

但我无法使用此序列化程序捕获响应

序列化程序.PY

class performance(viewsets.ModelViewSet):

    queryset = Leads.objects.select_related('channelId'
        ).values("channelId__channelName").annotate(tcount=Count('channelId'))

    serializer_class = teamwise_lead_performance_serializer

class channel_serializer(serializers.ModelSerializer):
    class Meta:
        model = Channels
        fields = ['channelName']


class performance_serializer(serializers.ModelSerializer):
    tcount = serializers.IntegerField()
    channel = channel_serializer(many=True, read_only=True)

    class Meta:
        model = Leads
        fields = ['tcount', 'channel']

实际结果：

[
    {
        "tcount": 88
    },
    {
        "tcount": 25
    },
    {
        "tcount": 31
    },
    ...
]

预期成果：

[
    {
        "channelName": "abc",
        "tcount": 88
    },
    {
        "channelName": "def",
        "tcount": 25
    },
    {
        "channelName": "ghi",
        "tcount": 31
    },
    ...
]

我尝试了以下方法：

class performance_serializer(serializers.ModelSerializer):
    tcount = serializers.IntegerField()
    channelName = serializers.CharField(source='channelId__channelName')

    class Meta:
        model = Leads
        fields = ['tcount', 'channelName']

class performance(viewsets.ModelViewSet):
    queryset = Leads.objects.select_related('channelId'
        ).values("channelId__channelName").annotate(tcount=Count('channelId'))
    serializer_class = performance_serializer

型号.py

class Channels(models.Model):
    id = models.IntegerField(primary_key=True)
    channelName = models.CharField(max_length=20, default=None)

    class Meta:
        db_table = "table1"

class Leads(models.Model):
    id = models.IntegerField(primary_key=True)
    channelId = models.ForeignKey(Channels, on_delete=models.CASCADE, db_column='channelId')

    class Meta:
        db_table = "table2"

为什么它没有得到

channelName

的响应？ 我做错了什么？ 谢谢你的建议

编辑 当我尝试Mehren的答案时，我得到以下错误：

尝试获取序列化程序性能\u序列化程序上的字段channelName的值时出现键错误。序列化程序字段的名称可能不正确，并且与dict实例上的任何属性或键都不匹配。原始异常文本为：“channelId”

---

如果您只想获得channelName，那么最好使用

channelName = serializers.CharField(source='channelId.channelName') 

另外，请修正你的语法。您没有遵守pep8标准

编辑

class PerformanceSerializer(serializers.ModelSerializer):
    tcount = serializers.IntegerField()
    channelName = serializers.CharField(source='channelId.channelName') 

    class Meta:
        model = Leads
        fields = ['tcount', 'channelName']

queryset = Leads.objects.select_related('channelId').values("channelId__channelName").annotate(tcount=Count('channelId'))

编辑

class PerformanceSerializer(serializers.ModelSerializer):
    tcount = serializers.IntegerField()
    channelName = serializers.CharField(source='channelId.channelName') 

    class Meta:
        model = Leads
        fields = ['tcount', 'channelName']

queryset = Leads.objects.select_related('channelId').values("channelId__channelName").annotate(tcount=Count('channelId'))

---

从您的视图中删除

.values（“channelId\uu channelName”）

部分

我设法使其与以下内容一起工作：

class performance_serializer(serializers.ModelSerializer):
    tcount = serializers.IntegerField()
    channelName = serializers.CharField(source='channelId__channelName')

    class Meta:
        model = Leads
        fields = ['tcount', 'channelName']

class performance(viewsets.ModelViewSet):
    queryset = Leads.objects.select_related('channelId'
        ).values("channelId__channelName").annotate(tcount=Count('channelId'))
    serializer_class = performance_serializer

话虽如此，我还是强烈建议您遵循命名和命名惯例

下面是您的代码的外观，如下所述：

class Channel(models.Model):
    id = models.IntegerField(primary_key=True)
    channel_name = models.CharField(max_length=20, default=None)

class Lead(models.Model):
    id = models.IntegerField(primary_key=True)
    channel = models.ForeignKey(Channel, on_delete=models.CASCADE)

class PerformanceSerializer(serializers.ModelSerializer):
    channel_count = serializers.IntegerField()
    channel_name = serializers.CharField(source='channel__channel_name')

    class Meta:
        model = Lead
        fields = ['channel_count', 'channel_name']

class PerformanceViewSet(viewsets.ModelViewSet):
    queryset = Lead.objects.select_related('channel'
        ).values("channel__channel_name").annotate(channel_count=Count('channel'))
    serializer_class = PerformanceSerializer

---

这样做的主要目的是不更改

ForeignKey

列的默认名称！这使得使用相关模型变得更加混乱，并且可能是您出现问题的首要原因（尽管我无法证明这一点）

如果我添加

channelName=serializers.CharField（source='channel.name'）

？在performance_serializer中，它为我提供了

字段“channel”已在serializer performance_serializer上声明，但尚未包含在“fields”选项中。

。。。。。。。我在问题中添加了模型我编辑了答案。基本上，对于DRF序列化程序，您手动定义的字段也必须存在于Meta.fields中。现在，在尝试获取序列化程序“performance\u serializer”上的字段“channelName”的值时，我遇到了

get keyrorm。\n序列化程序字段的名称可能不正确，并且与“dict”实例上的任何属性或键都不匹配。\n原始异常文本为：“频道”。

我已经根据您的型号定义编辑了答案。希望有帮助！试图获取序列化程序“performance\u serializer”上字段“channelName”的值时，geting

get-KeyError仍然存在。序列化程序字段的名称可能不正确，并且与“dict”实例上的任何属性或键都不匹配。原始异常文本为：“channelId”。

您在

Lead

模型中有一个输入错误，在

channel

字段中：相关型号名称应为

channel

now。它只有一个字符，编辑必须更改至少6个字符，所以我必须找到其他东西来挑剔。。。最好自己解决：）还要注意，每个潜在客户只能有一个相关频道。因此，设置

channel=channel\u序列化程序（many=True，…）

没有意义-这里不能有很多通道。正如所提供的答案所表明的那样，把它变成查尔菲尔德是一个更好的主意。