如何在SQLAlchemy中为Flask创建具有自动递增主键的关联表？

pip install SQLAlchemy Flask

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = '数据库连接字符串'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)

class Parent(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    children = db.relationship('Child', backref='parent', lazy=True)

class Child(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    parent_id = db.Column(db.Integer, db.ForeignKey('parent.id'), nullable=False)

db.create_all()

parent = Parent()
child = Child()
parent.children.append(child)
db.session.add(parent)
db.session.commit()