Python 如何在Django rest框架序列化程序的关系模型中获得额外的列？

我有

Category

和

Article

模型，

Article

有一个外键reference

Category

，在我的

序列化程序中

我可以在Category模型中获得name列，因为使用了str方法，但是如何在

Category

模型中获得其他列呢

models.py：

# blog category models
class Category(models.Model):
    #id = models.IntegerField(primary_key=True,help_text='primary key',auto_created=True)
    name = models.CharField(max_length=50,help_text='category name')
    description = models.TextField(default='',help_text='category description')
    coverimg = models.CharField(max_length=200,default='',help_text='category front cover image')
    covercolor = models.CharField(max_length=7,default='#ffffff',help_text='color for each category background')
    totalitems = models.IntegerField(default=0,help_text='total items for each category')
    createtime = models.DateTimeField(auto_now_add=True)
    modifytime = models.DateTimeField(auto_now=True)

    categories = models.Manager()

    class Meta:
        db_table = 'article_category'
    def __str__(self):
        return self.name

#blog article models
class Article(models.Model):
    STATUS = (
        (0,'on'),
        (1,'off')
    )
    #id = models.IntegerField(primary_key=True,help_text='primary key',auto_created=True)
    category = models.ForeignKey(Category,related_name='articles', help_text='foreigner key reference Category')
    #author = models.ForeignKey(myadmin.User, help_text='foreigner key reference myadmin User')
    title = models.CharField(max_length=100, help_text='article title')
    description = models.TextField(help_text='article brief description')
    content = models.TextField(help_text='article content')
    like = models.IntegerField(default=0,help_text='like numbers')
    secretcode = models.CharField(max_length=512,help_text='who has the code can scan')
    status = models.IntegerField(choices=STATUS,help_text='status of the article')
    createtime = models.DateTimeField(auto_now_add=True,help_text='time that first created')
    modifytime = models.DateTimeField(auto_now=True,help_text='time when modified')

    articles = models.Manager()

    def __str__(self):
        return self.title
    class Meta:
        db_table = 'article'

    def save(self, *args, **kwargs):
        if not self.id:
            Category.categories.filter(pk=self.category.pk).update(totalitems = F('totalitems')+1)
        super(Article,self).save(*args, **kwargs)

serializers.py：

#   Article catalog
class ArticleCatalogSerializer(serializers.ModelSerializer):
    category = serializers.StringRelatedField()
    articletags = serializers.StringRelatedField(many=True)
    covercolor = serializers.StringRelatedField()
    class Meta:
        model = Article
        fields = ('id', 'title', 'category', 'articletags', 'description', 'like', 'createtime', 'covercolor')

covercolor=serializers.StringRelatedField（）将导致错误：

Article'对象没有属性'covercolor

，我更改为：

已更改序列化程序。py:

#   category serializer for ArticleCatalogSerializer for nested relationship
class CategoryNestedRelationshipSerializer(serializers.ModelSerializer):
    class Meta:
        model = Category
        fields = ('covercolor',)

#   Article catalog
class ArticleCatalogSerializer(serializers.ModelSerializer):
    category = serializers.StringRelatedField()
    articletags = serializers.StringRelatedField(many=True)
    covercolor = CategoryNestedRelationshipSerializer(read_only=True)
    class Meta:
        model = Article
        ields = ('id', 'title', 'category', 'articletags', 'description', 'like', 'createtime', 'covercolor')

Got AttributeError when attempting to get a value for field `covercolor` on serializer `ArticleCatalogSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `Article` instance.
Original exception text was: 'Article' object has no attribute 'covercolor'.

出现错误：

#   category serializer for ArticleCatalogSerializer for nested relationship
class CategoryNestedRelationshipSerializer(serializers.ModelSerializer):
    class Meta:
        model = Category
        fields = ('covercolor',)

#   Article catalog
class ArticleCatalogSerializer(serializers.ModelSerializer):
    category = serializers.StringRelatedField()
    articletags = serializers.StringRelatedField(many=True)
    covercolor = CategoryNestedRelationshipSerializer(read_only=True)
    class Meta:
        model = Article
        ields = ('id', 'title', 'category', 'articletags', 'description', 'like', 'createtime', 'covercolor')

Got AttributeError when attempting to get a value for field `covercolor` on serializer `ArticleCatalogSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `Article` instance.
Original exception text was: 'Article' object has no attribute 'covercolor'.

---

如何实现这一点？

StringRelatedField将发出相关字段的字符串表示

要保持“平面”格式，您需要编写一个字段

---

或者，如果希望包含对类别的引用，则需要PrimaryKeyRelatedField或相关模型。

在编辑中，将ArticleCatalogSerializer更改为

class ArticleCatalogSerializer(serializers.ModelSerializer):
    category = CategoryNestedRelationshipSerializer()
    class Meta:
        model = Article

您将获得此格式的输出

{
"id": 1,
"category": {
"covercolor": "#ffffff"
},
"title": "sa",
"description": "bhjghj",
"content": "sda",
"like": 0,
"secretcode": "77",
"status": 0,
"createtime": "2015-04-18T07:52:57.230110Z",
"modifytime": "2015-04-18T07:52:57.230135Z"
}

如果您想要类别的任何其他列，可以像下面这样包含在类别序列化程序中

class CategoryNestedRelationshipSerializer(serializers.ModelSerializer):
    class Meta:
        model = Category
        fields = ('covercolor','name','description')

---

我改为covercolor=serializers.PrimaryKeyRelatedField（read_only=True）仍然不起作用~Ahh，如果你正在序列化一个文章模型，那是因为covercolor属性（它在相关类别上）。要保持“平面”格式，您需要编写一个自定义字段。我已经编辑了我的问题，看看，我哪里错了？这非常有效。在模型中，如果引用与关系模型相关的任何列，外键应该是入口，在前一种情况下，我只引用类别外键，它返回其名称，只有一列，若有很多列，你们应该在关系模型上查询它们，并将其设置为嵌套关系并插入到文章中，这是一个数组。我想对了吗？节省了我的时间。。。谢谢