models.py

from database import Base
from sqlalchemy import Column, Integer, Boolean, Text, String, ForeignKey
from sqlalchemy.orm import relationship
from sqlalchemy_utils.types import ChoiceType


class User(Base):
    __tablename__='user'
    id=Column(Integer, primary_key=True)
    username=Column(String(25), unique=True)
    email=Column(String(70), unique=True)
    password=Column(Text, nullable=True)
    is_staff=Column(Boolean, default=False)
    is_active=Column(Boolean, default=False)
    orders=relationship('Order', back_populates='user')  # one-to-many

    def __repr__(self):
        return f"<user {self.username}"


class Order(Base):
    ORDER_STATUSES=(
        ('PENDING', 'pending'),
        ('IN_TRANSIT', 'in_transit'),
        ('DELIVIRED', 'delivered')
    )
    __tablename__='orders'
    id=Column(Integer, primary_key=True)
    quantity=Column(Integer, nullable=False)
    order_statuses=Column(ChoiceType(choices=ORDER_STATUSES), default="PENDING")
    user_id=Column(Integer, ForeignKey('user.id'))
    user=relationship('User', back_populates='orders')  # many-to-one
    product_id=Column(Integer, ForeignKey('product.id'))
    product=relationship('Product', back_populates='orders')  # many-to-one


    def __repr__(self):
        return f"<order {self.id}"


class Product(Base):
    __tablename__='product'
    id=Column(Integer, primary_key=True)
    name=Column(String(100))
    price=Column(Integer)
    orders=relationship('Order', back_populates='product')  # one-to-many

    def __repr__(self):
        return f"<product {self.name}"