如何将ERD转换为Django model与schemas？

from django.db import models
from django.utils import timezone

class Category(models.Model):
    name = models.CharField(max_length=100, verbose_name="分类名称")
    description = models.TextField(blank=True, null=True, verbose_name="分类描述")
    created_at = models.DateTimeField(default=timezone.now, verbose_name="创建时间")

    class Meta:
        db_table = "category"
        verbose_name = "商品分类"
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.name


class Product(models.Model):
    name = models.CharField(max_length=200, verbose_name="商品名称")
    description = models.TextField(blank=True, null=True, verbose_name="商品描述")
    price = models.DecimalField(max_digits=10, decimal_places=2, verbose_name="商品价格")
    stock = models.IntegerField(default=0, verbose_name="库存数量")
    category = models.ForeignKey(Category, on_delete=models.PROTECT, related_name="products", verbose_name="所属分类")
    created_at = models.DateTimeField(default=timezone.now, verbose_name="创建时间")

    class Meta:
        db_table = "product"
        verbose_name = "商品信息"
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.name


class Customer(models.Model):
    name = models.CharField(max_length=100, verbose_name="客户姓名")
    email = models.EmailField(unique=True, verbose_name="客户邮箱")
    phone = models.CharField(max_length=20, verbose_name="联系电话")
    address = models.TextField(verbose_name="收货地址")
    created_at = models.DateTimeField(default=timezone.now, verbose_name="创建时间")

    class Meta:
        db_table = "customer"
        verbose_name = "客户信息"
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.name


class Order(models.Model):
    ORDER_STATUS_CHOICES = [
        ("pending", "待支付"),
        ("paid", "已支付"),
        ("shipped", "已发货"),
        ("completed", "已完成"),
        ("cancelled", "已取消"),
    ]
    customer = models.ForeignKey(Customer, on_delete=models.CASCADE, related_name="orders", verbose_name="所属客户")
    order_date = models.DateTimeField(default=timezone.now, verbose_name="下单时间")
    total_amount = models.DecimalField(max_digits=12, decimal_places=2, verbose_name="订单总金额")
    status = models.CharField(max_length=20, choices=ORDER_STATUS_CHOICES, default="pending", verbose_name="订单状态")
    created_at = models.DateTimeField(default=timezone.now, verbose_name="创建时间")

    class Meta:
        db_table = "order"
        verbose_name = "订单信息"
        verbose_name_plural = verbose_name

    def __str__(self):
        return f"订单{self.id} - {self.customer.name}"


class OrderItem(models.Model):
    order = models.ForeignKey(Order, on_delete=models.CASCADE, related_name="order_items", verbose_name="所属订单")
    product = models.ForeignKey(Product, on_delete=models.PROTECT, related_name="order_items", verbose_name="对应商品")
    quantity = models.IntegerField(default=1, verbose_name="购买数量")
    unit_price = models.DecimalField(max_digits=10, decimal_places=2, verbose_name="成交单价")
    created_at = models.DateTimeField(default=timezone.now, verbose_name="创建时间")

    class Meta:
        db_table = "order_item"
        verbose_name = "订单项"
        verbose_name_plural = verbose_name

    def __str__(self):
        return f"{self.order.id} - {self.product.name} * {self.quantity}"

from rest_framework import serializers
from .models import Category, Product, Customer, Order, OrderItem

class CategorySerializer(serializers.ModelSerializer):
    class Meta:
        model = Category
        fields = "__all__"


class ProductSerializer(serializers.ModelSerializer):
    category_name = serializers.CharField(source="category.name", read_only=True)
    class Meta:
        model = Product
        fields = ["id", "name", "description", "price", "stock", "category", "category_name", "created_at"]


class CustomerSerializer(serializers.ModelSerializer):
    class Meta:
        model = Customer
        fields = "__all__"


class OrderItemSerializer(serializers.ModelSerializer):
    product_name = serializers.CharField(source="product.name", read_only=True)
    class Meta:
        model = OrderItem
        fields = ["id", "product", "product_name", "quantity", "unit_price", "created_at"]


class OrderSerializer(serializers.ModelSerializer):
    customer_name = serializers.CharField(source="customer.name", read_only=True)
    order_items = OrderItemSerializer(many=True, read_only=True)
    class Meta:
        model = Order
        fields = ["id", "customer", "customer_name", "order_date", "total_amount", "status", "order_items", "created_at"]

• 外键删除策略根据通用业务场景设置：商品分类和商品关联用PROTECT避免分类被误删导致商品数据异常，客户和订单关联用CASCADE实现删除客户时同步删除对应订单，可自行调整
• 序列化器额外添加了关联表的名称字段，满足接口返回常用字段的需求，不需要可自行删除
• 所有字段的长度、精度、可选属性都可以根据实际业务需求调整

内容的提问来源于stack exchange，提问作者djangodeveloper