在TableField中自动添加当前日期时间

CREATE TABLE my_table (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(255),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

import datetime

current_datetime = datetime.datetime.now()

CREATE TRIGGER my_table_trigger
BEFORE INSERT ON my_table
FOR EACH ROW
SET NEW.created_at = NOW();

from sqlalchemy import Column, Integer, String, DateTime
from sqlalchemy.sql import func
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class MyTable(Base):
    __tablename__ = 'my_table'

    id = Column(Integer, primary_key=True)
    name = Column(String)
    created_at = Column(DateTime, server_default=func.now())