数据库未从Ajax POST更新

from flask import Flask, request, jsonify
import mysql.connector

app = Flask(__name__)

@app.route('/update_data', methods=['POST'])
def update_data():
    data = request.get_json()
    
    # 数据验证
    if not data or 'id' not in data or 'value' not in data:
        return jsonify({'error': 'Invalid data'}), 400
    
    try:
        # 连接数据库
        db = mysql.connector.connect(
            host="localhost",
            user="yourusername",
            password="yourpassword",
            database="yourdatabase"
        )
        
        cursor = db.cursor()
        
        # 更新数据库
        sql = "UPDATE yourtable SET value = %s WHERE id = %s"
        val = (data['value'], data['id'])
        cursor.execute(sql, val)
        
        db.commit()
        
        return jsonify({'success': True}), 200
    
    except mysql.connector.Error as err:
        return jsonify({'error': str(err)}), 500
    
    finally:
        if db.is_connected():
            cursor.close()
            db.close()

if __name__ == '__main__':
    app.run(debug=True)