我正在修补Django Rest框架,以构建一个api,该api可以处理电子元件的物料清单(BoM)。你知道吗
我使用的是django多态和django rest多态,因此我可以为组件使用多态模型(它们有共享属性,但我仍然希望以大致相同的方式处理它们)。多态模型非常适合这个目的)。你知道吗
一切都很好,直到我介绍了一个'通过'属性多对多的关系。我想要的是一个BoM表,有几个不同的组成部分,每个与数量,例如,BoM1有2x470k电阻和3x 100uF电容器。你知道吗
你知道吗型号.py:(删减了一点,以免这篇文章成为史诗小说)
class BoM(models.Model):
"""Bill of Materials: a list of all parts and their quantities for a given pedal"""
pedal = models.ForeignKey(Pedal, on_delete=models.CASCADE)
variant = models.CharField(max_length=100, blank=True)
electronic_components = models.ManyToManyField(
'ElectronicComponent', through='ElectronicComponentQty', blank=True)
class Meta:
verbose_name = 'Bill of materials'
verbose_name_plural = 'Bills of materials'
def __str__(self):
return str(self.pedal)
class ElectronicComponent(PolymorphicModel):
"""Shared data model for electronic components"""
value = models.CharField(max_length=20)
datasheet = models.FileField(upload_to='uploads/components', blank=True)
def __str__(self):
return self.value
class ElectronicComponentQty(models.Model):
"""Combination of resistor and quantity"""
bom = models.ForeignKey(BoM, on_delete=models.CASCADE)
component = models.ForeignKey(
ElectronicComponent, on_delete=models.CASCADE)
quantity = models.PositiveIntegerField(default=1)
class Meta:
verbose_name = 'Elecronic component quantity'
verbose_name_plural = 'Electronic component quantities'
class Resistor(ElectronicComponent):
"""Resistor data model"""
WATTAGES = [('1/4w', '1/4w'), ('1/8w', '1/8w')]
wattage = models.CharField(max_length=4, choices=WATTAGES, default='1/4w')
class Capacitor(ElectronicComponent):
"""Capacitors (all kinds)"""
VOLTAGE_RATINGS = [
('16V', '16V'),
('35V/50V', '35V/50V'),
]
CAP_TYPES = [
('ceramic disk', 'ceramic disk'),
('film', 'film'),
('electrolytic', 'electrolytic'),
('tantalum', 'tantalum'),
('other', 'other'),
]
capacitor_type = models.CharField(
max_length=20, choices=CAP_TYPES, default='film')
voltage_rating = models.CharField(
max_length=10, choices=VOLTAGE_RATINGS, blank=True)
你知道吗序列化程序.py地址:
class ElectronicComponentSerializer(serializers.ModelSerializer):
class Meta:
model = ElectronicComponent
fields = '__all__'
class ElectronicComponentQtySerializer(serializers.ModelSerializer):
class Meta:
model = ElectronicComponentQty
fields = '__all__'
class BoMSerializer(serializers.ModelSerializer):
electronic_components = ElectronicComponentQtySerializer(
many=True, read_only=True)
class Meta:
model = BoM
fields = '__all__'
class ResistorSerializer(serializers.ModelSerializer):
class Meta:
model = Resistor
fields = '__all__'
class CapacitorSerializer(serializers.ModelSerializer):
class Meta:
model = Capacitor
fields = '__all__'
class ElectronicComponentPolySerializer(PolymorphicSerializer):
model_serializer_mapping = {
Resistor: ResistorSerializer,
Capacitor: CapacitorSerializer,
}
用这段代码我可以创建EletronicComponentQty对象没有问题。但是,当我尝试列出BoM表(通过序列化程序)时,我得到:
属性错误位于/pedalparts/boms/
在尝试获取上的字段bom
的值时获取AttributeError
序列化程序ElectronicComponentQtySerializer
。
序列化程序字段的名称可能不正确,并且与任何字段都不匹配
Capacitor
实例上的属性或键。
最初的异常文本是:“Capacitor”对象没有属性
'物料清单'。你知道吗
有人知道我怎么解决这个问题吗?我愿意接受任何改变,使这项工作。你知道吗
因为
BoM
模型上的electronic_components
指的是ElectronicComponent
模型,所以它不应该使用ElectronicComponentQtySerializer
,而是可以序列化正确的实例,很可能是ElectronicComponentSerializer
或ElectronicComponentPolySerializer
。你知道吗相关问题 更多 >
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