sqlalchemy实现时间列自动更新教程

import datetime
from uuid import uuid4
from sqlalchemy import Column, Integer, String, DateTime, Boolean
from sqlalchemy_demo.connect import Base
class UserModule(Base):
  """
  创建一个用户的数据模型
  """
  __tablename__ = 'user'

  uuid = Column(String(36), unique=True, nullable=False, default=lambda: str(uuid4()), comment='uuid')
  id = Column(Integer, primary_key=True, autoincrement=True, comment='用户id')
  user_name = Column(String(30), nullable=False, unique=True, comment='用户名')
  password = Column(String(64), nullable=False, comment='用户密码')
  createtime = Column(DateTime, default=datetime.datetime.now, comment='创建时间')
  updatetime = Column(DateTime, default=datetime.datetime.now, comment='修改时间')
  is_lock = Column(Boolean, default=False, nullable=False, comment='是否锁住用户')

from uuid import uuid4
from sqlalchemy import Column, Integer, String, DateTime, Boolean, TIMESTAMP, func
from sqlalchemy.orm import relationship

from sqlalchemy_demo.connect import Base

class UserModule(Base):
  """
  创建一个用户的数据模型
  """
  __tablename__ = 'user'

  uuid = Column(String(36), unique=True, nullable=False, default=lambda: str(uuid4()), comment='uuid')
  id = Column(Integer, primary_key=True, autoincrement=True, comment='用户id')
  user_name = Column(String(30), nullable=False, unique=True, comment='用户名')
  password = Column(String(64), nullable=False, comment='用户密码')
  createtime = Column(DateTime, server_default=func.now(), comment='创建时间')
  # onupdate设置自动更改
  updatetime = Column(DateTime, server_default=func.now(), onupdate=func.now(), comment='修改时间')
  is_lock = Column(Boolean, default=False, nullable=False, comment='是否锁住用户')

class Status(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  submit_time = db.Column(db.DateTime, default=datetime.now())

from datetime import datetime, timedelta
 
NOW = datetime.utcnow()
last_24h_submits_count = []
for h in xrange(1,25):
  count = session.query(Status).filter(Status.submit_time.between(NOW - timedelta(seconds=h*3600-1), NOW - timedelta(hours=h-1))).count()
  last_24h_submits_count.append(count)