在flask sqlachemy的三列关联表中插入数据

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

class A(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    b_id = db.Column(db.Integer, db.ForeignKey('b.id'))
    c_id = db.Column(db.Integer, db.ForeignKey('c.id'))
    b = db.relationship('B', backref='a')
    c = db.relationship('C', backref='a')

class B(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))

class C(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))

from flask import Flask

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = '数据库连接地址'
db.init_app(app)

from flask import request

@app.route('/insert_data', methods=['POST'])
def insert_data():
    data = request.json  # 假设通过POST请求传递的数据为JSON格式

    # 创建A、B、C对象并设置属性
    a = A()
    a.name = data['a_name']

    b = B()
    b.name = data['b_name']

    c = C()
    c.name = data['c_name']

    # 建立关联关系
    a.b = b
    a.c = c

    # 将对象添加到会话中并提交到数据库
    db.session.add(a)
    db.session.add(b)
    db.session.add(c)
    db.session.commit()

    return '数据插入成功'