python - Django REST 框架中的外键值

Question

模型.py:

class Station(models.Model):
    station = models.CharField()

class Flat(models.Model):
    station = models.ForeignKey(Station, related_name="metro")
    # another fields

然后在 serializers.py 中:

class StationSerializer(serializers.ModelSerializer):
    station = serializers.RelatedField(read_only=True)

    class Meta:
        model = Station


class FlatSerializer(serializers.ModelSerializer):
    station_name = serializers.RelatedField(source='station', read_only=True)

    class Meta:
        model = Flat
        fields = ('station_name',)

我有一个错误:

NotImplementedError: RelatedField.to_representation() must be implemented. If you are upgrading from REST framework version 2 you might want ReadOnlyField.
I read this, but it does not help me.
How to fix that?
Thanks!

Answer 1

RelatedField 是所有处理关系的字段的基类。通常你不应该使用它，除非你将它子类化为一个自定义字段。

在您的情况下，您甚至根本不需要相关字段。您只是在寻找一个只读的单个外键表示，因此您可以只使用 CharField。

class StationSerializer(serializers.ModelSerializer):
    station = serializers.CharField(read_only=True)

    class Meta:
        model = Station


class FlatSerializer(serializers.ModelSerializer):
    station_name = serializers.CharField(source='station.name', read_only=True)

    class Meta:
        model = Flat
        fields = ('station_name', )

您似乎还需要 FlatSerializer 中的 Station 对象的 name。您应该让 source 指向确切的字段，因此我为您将其更新为 station.name。