Question

这些是我的django模型。

数据库模型的说明：
thinkpad 是 laptop equipment的{{1}}。 laptop子类别有一个名为的subcategory >电子。
现在笔记本电脑可以有许多category，例如attributes。

问题：
找出所有具有{em> category_id = 1 的processor,ram,color,screen_size及其equipment。

模型：

equipment detail ,subcategory_name and attribute names,value

所需的输出：

class Category(models.Model):
    category_id = models.AutoField(primary_key=True, default=None)
    category_name = models.CharField(max_length=15, unique=True)
    created_at = models.DateTimeField(auto_now_add=True)
    last_modified = models.DateTimeField(auto_now=True)

    def __str__(self):
        return str(self.category_id)+","+self.category_name

    class Meta:
        db_table = "category"


class Subcategory(models.Model):
    subcategory_id = models.AutoField(primary_key=True, default=None)
    category = models.ForeignKey(
        Category, on_delete=models.CASCADE, related_name="category_subc", verbose_name="category_id")
    subcategory_name = models.CharField(max_length=15, unique=True)
    created_at = models.DateTimeField(auto_now_add=True)
    last_modified = models.DateTimeField(auto_now=True)

    def __str__(self):
        return str(self.subcategory_id)+","+self.subcategory_name

    class Meta:
        db_table = "subcategory"


class Equipment(models.Model):
    equipment_id = models.AutoField(primary_key=True, default=None)
    subcategory = models.ForeignKey(
        Subcategory, on_delete=models.CASCADE, related_name="subcategory_eq", verbose_name="subcategory_id")
    created_at = models.DateTimeField(auto_now_add=True)
    last_modified = models.DateTimeField(auto_now=True)

    def __str__(self):
        return str(self.equipment_id)

    class Meta:
        db_table = "equipment"


class Attribute(models.Model):
    attribute_id = models.AutoField(primary_key=True, default=None)
    attribute_name = models.CharField(max_length=15, unique=True)
    subcategory = models.ManyToManyField(
        Subcategory, through="SubcategoryAttributeMap")
    created_at = models.DateTimeField(auto_now_add=True)
    last_modified = models.DateTimeField(auto_now=True)

    def __str__(self):
        return str(self.attribute_id)+","+self.attribute_name

    class Meta:
        db_table = "attribute"


class SubcategoryAttributeMap(models.Model):
    id = models.AutoField(primary_key=True, default=None)
    subcategory = models.ForeignKey(
        Subcategory, on_delete=models.CASCADE, related_name="subcategory_sub_attr_map", verbose_name="subcategory_id")
    attribute = models.ForeignKey(
        Attribute, on_delete=models.CASCADE, related_name="attribute_sub_attr_map", verbose_name="attribute_id")
    created_at = models.DateTimeField(auto_now_add=True)
    last_modified = models.DateTimeField(auto_now=True)

    def __str__(self):
        return str(self.id)

    class Meta:
        db_table = "subcategory_attribute_map"


class EquipmentDetail(models.Model):
    equipment_detail_id = models.AutoField(primary_key=True, default=None)
    equipment = models.ForeignKey(
        Equipment, on_delete=models.CASCADE, related_name="equipment_eqdetail", verbose_name="equipment_id")
    attribute = models.ForeignKey(
        Attribute, on_delete=models.CASCADE, related_name="attribute_eqdetail", verbose_name="attribute_id")
    value = models.CharField(max_length=15)
    created_at = models.DateTimeField(auto_now_add=True)
    last_modified = models.DateTimeField(auto_now=True)

    def __str__(self):
        return str(self.equipment_detail_id)+","+self.value

    class Meta:
        db_table = "equipment_detail"

Answer 1

尝试一下：

@cntrlst

此查询将有2个sql查询，并且将以您所需的格式返回数据。

Answer 2

我得到了答案。

equipments = Equipment.objects.filter(subcategory__category__category_id=1)  


all_equipments_data = []  

# iterate over each equipment  

for equipment in equipments:
    single_equipment_data = {}  
    single_equipment_data['equipment_id'] = equipment.equipment_id
    single_equipment_data['subcategory__name'] = equipment.subcategory.subcategory_name  

    attributes_detail_of_equipment = []  

# iterate over each equipmentdetail of single equipment
    for eqdetail in equipment.equipment_eqdetail.all(): 

       attributes_detail_of_equipment.append({'attribute_name':eqdetail.attribute.attribute_name,'attribute_value':eqdetail.value})  

       single_equipment_data['attribute_detail'] = attributes_detail_of_equipment  

all_equipments_data.append(single_equipment_data)

使用Django ORM查询获取模型对象的所有相关详细信息？

2 个答案: