Django Restful 模型外键 - 指定 From 和 To 字段

Question

我是 Django 新手，并试图了解如何在模型中设置数据库关系。我有以下两种型号：

class BusinessTypes(models.Model):
    categoryID = models.AutoField(db_column='TypeID', primary_key=True)  # Field name made lowercase.
    category = models.CharField(db_column='type', max_length=200)
    newtype = models.CharField(db_column='newType', max_length=200)  # Field name made lowercase.
    dec = models.CharField(max_length=255)
    tabsize = models.CharField(db_column='tabSize', max_length=10)  # Field name made lowercase.
    #subcategory = models.ForeignKey(BusinessTypesSub, to_field='Type_ID')

    class Meta:
        managed = False
        db_table = 'business_types'
        app_label = 'sapi'

class BusinessTypesSub(models.Model):
    subcategoryID = models.AutoField(db_column='Type_subID', primary_key=True)  # Field name made lowercase.
    categoryID = models.IntegerField(db_column='Type_ID')  # Field name made lowercase.
    status = models.IntegerField()
    showpub = models.IntegerField(db_column='showPub')  # Field name made lowercase.
    showcity = models.CharField(db_column='showCity', max_length=20)  # Field name made lowercase.
    subcategory = models.CharField(db_column='sub', max_length=255)
    sub_alternative = models.CharField(max_length=255)
    category = models.ForeignKey(BusinessTypes,from_field='Type_ID', to_field='TypeID')

    class Meta:
        managed = False
        db_table = 'business_types_sub'
        app_label = 'api'

business_types 和business_types_sub 表之间存在一对多的关系。我想设置一个外键关系，以便如果我创建一个通过 BusinessTypesSub 调用序列化程序的视图，我可以访问 BusinessTypesModel 中类别字段的值。外键关系应该是从 BusinessTypesSub 字段“Type_ID”到 BusinessTypes 字段“TypeID”。

我怎样才能创建这个？我尝试将以下内容添加到 BusinessTypesSub 模型中，但它只会创建以下错误：

category = models.ForeignKey(BusinessTypes,to_field='TypeID')

BusinessTypes has no field named 'TypeID'

另外，我如何在视图/序列化器中调用它。例如，我如何将“类别”添加到以下序列化程序：

class BusinessTypesSubSerializer(serializers.ModelSerializer):
    category = serializers.RelatedField(source='BusinessType', read_only=True)

    class Meta:
        model = BusinessTypesSub
        fields = ('categoryID', 'category', 'subcategoryID', 'subcategory')

Answer 1

你指定的to_field错误，应该是BusinessType类的categoryID字段名，而不是数据库中的列名：

category = models.ForeignKey(BusinessTypes, to_field='categoryID')

要在 BusinessTypesSubSerializer 中显示类别，您可以从此处定义的多个选项中进行选择：http://www.django-rest-framework.org/api-guide/relations/。例如。对于 StringRelatedField，您可以定义：

class BusinessTypesSubSerializer(serializers.ModelSerializer):
    category = serializers.StringRelatedField(read_only=True)

    class Meta:
        model = BusinessTypesSub
        fields = ('categoryID', 'category', 'subcategoryID', 'subcategory')