Peewee:如何更新特定字段?

代替 u.save() 使用:

u.save(only=[User.last_login])

API's documentation 说:

仅(列表) 要持久化的字段列表。如果提供,则只会持久化给定的字段。

您可以使用 only save() http://docs.peewee-orm.com/en/latest/peewee/api.html#Model.save

当用户登录到系统时,我想更新last_登录。我使用了以下代码行:

User.update({User.last_login: datetime.datetime.now()}).where(User.username == 'whatever').execute()

以下代码将演示如何在数据库中创建、获取和更新记录:

now = datetime.datetime.now()

# create a user
u = User.create(username="user1", password="bla", last_login=now)
# now `u` has your user, you can do: print u.username, u.password, u.last_login

# get an existing user from the db
u = User.get(User.username == "user1")
print u.username, u.password, u.last_login

sleep(1)
now = datetime.datetime.now()

# update an existing user
u = User.update(password="blabla", last_login=now).where(User.username == "user1")
u.execute()

如果只想保存修改过的字段,可以使用以下方法:

class User(Model):
    username = CharField(unique=True)
    password = CharField()
    last_login = DateTimeField(default=datetime.datetime.now())

    class Meta:
        database = MySQLDatabase('mydb', user='root', charset='123456')

        # This method saves only modefied fields
        only_save_dirty = True

u=User(username="user1", last_login=datetime.datetime.now())
u.save()