您可以重写模型类上的save方法。

class Something(Model):
    created = DateTimeField(default=datetime.datetime.now)
    modified = DateTimeField

    def save(self, *args, **kwargs):
        self.modified = datetime.datetime.now()
        return super(Something, self).save(*args, **kwargs)

只要在MySQL中使用TIMESTAMP类型即可。每当行更新时，此字段将自动更新。
在model：

last_updated = peewee.TimestampField()

你也可以重写update方法来提供。就像coleifer所做的那样：

class Something(Model):
    created = DateTimeField(default=datetime.datetime.now)
    modified = DateTimeField

    @classmethod
    def update(cls, *args, **kwargs):
        kwargs['modified'] = datetime.datetime.now()
        return super(Something, cls).save(*args, **kwargs)

    def save(self, *args, **kwargs):
        self.modified = datetime.datetime.now()
        return super(Something, self).save(*args, **kwargs)

也可以对replace方法执行相同的操作

from datetime import datetime

from peewee import (AutoField, CharField, DateTimeField, FloatField,
                    IntegerField, Model, MySQLDatabase, TextField, SQL)

from config import DataBaseConfig

mysql_client = MySQLDatabase(
    "your_database_name",
    host=DataBaseConfig.host,
    port=DataBaseConfig.port,
    user=DataBaseConfig.user,
    password=DataBaseConfig.password,
)

class CommonModel(Model):
    id = AutoField(verbose_name="primary key")
    create_time = DateTimeField(default=datetime.now, verbose_name="create time")
    update_time = DateTimeField(default=datetime.now, verbose_name="update time", constraints=[SQL('ON UPDATE CURRENT_TIMESTAMP')])

    class Meta:
        database = mysql_client

可以参考此文档，单列索引和约束！