from sqlalchemy import create_engine,Column,Integer,String,Float,DECIMAL,Boolean,Enum,Date,DateTime,Time,Text,and_,or_,ForeignKey
from sqlalchemy.dialects.mysql import LONGTEXT
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker,relationship,backref
from sqlalchemy.orm.collections import InstrumentedList
from sqlalchemy import func,Table
import random,time
import enum
from datetime import date,datetime
# 准备连接数据库基本信息
HOSTNAME = '127.0.0.1'
PORT = '3306'
DATABASE = 'first_sqlalchemy'
USERNAME = 'root'
PASSWORD = ''
# 按照上述的格式来 组织数据库信息
DB_URI = 'mysql+pymysql://{username}:{password}@{host}:{port}/{db}?charset=utf8'.format(username=USERNAME,password=PASSWORD,host=HOSTNAME,port=PORT,db=DATABASE)
# 创建数据库引擎
engine = create_engine(DB_URI)
Base = declarative_base(engine)
session = sessionmaker(engine)()
#排序方式1 :order_by
class Article(Base):
__tablename__ = 'article'
id = Column(Integer,primary_key=True,autoincrement=True)
title = Column(String(50),nullable=False)
create_time = Column(DateTime,nullable=False,default=datetime.now)
__mapper_args__ = {
# 'order_by':create_time # 正序
'order_by':create_time.desc() # 倒序
}
def __repr__(self):
return '<Article(title:%s,create_time:%s>'%(self.title,self.create_time)
def add_data():
Base.metadata.drop_all()
Base.metadata.create_all()
article1 = Article(title='title1')
session.add(article1)
session.commit()
time.sleep(3)
article2 = Article(title='title2')
session.add(article2)
session.commit()
def oper():
articles2 = session.query(Article).all()
print(articles2)
if __name__ == '__main__':
add_data()
# oper()

老师,我把数据库的表删了,还是这种情况