Python流行ORM框架sqlalchemy安装与使用教程

#进入虚拟环境
#执行
./python3 -m pip install

import sqlalchemy
print(sqlalchemy.__version__) # 1.1.15

from sqlalchemy import create_engine
# 连接本地test数据库
engine = create_engine("mysql://root:root@localhost/test?charset=utf8")

engine = create_engine("mysql+pymysql://root:root@localhost/test?charset=utf8")

result = engine.execute("select * from news")
print(result.fetchall())
#[(1, '本机新闻标题'), (2, '今天的新闻'), (3, '新闻标题1'), (4, '新闻标题2'), (5, '元组新闻1'), (6, '元组新闻2')]

from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()
from sqlalchemy import Column, Integer, String
class News(Base):
  # 表名称
  __tablename__ = 'news'
  # news表里id字段
  id = Column(Integer, primary_key=True, autoincrement=True)
  # news表里title字段
  title = Column(String(length=255), nullable=False)

from sqlalchemy import create_engine
from mappers.Infos import News
from sqlalchemy.orm import sessionmaker
# 连接本地test数据库
engine = create_engine("mysql+pymysql://root:root@localhost/test?charset=utf8")
# 创建会话
session = sessionmaker(engine)
mySession = session()
# 查询结果集
result = mySession.query(News).all()
print(result[0])

# 查询第一条
result = mySession.query(News).first()
print(result.title) #打印对象属性

# 查询id为2的
result = mySession.query(News).filter_by(id=2).first()
print(result.title)

# 查询id为2的
result = mySession.query(News).filter(News.id==2).first()

# 分页查询 0,2
result = mySession.query(News).filter(News.id>1).limit(2).offset(0).all()
print(result)

# 自定义过滤条件
result = mySession.query(News).filter(text("id>:id")).params(id=2).all()

result = mySession.query(News).get(3)
print(result.title)

# 新增
news = News(title="新增测试标题")
mySession.add(news)
mySession.commit()

#修改
mySession.query(News).filter(News.id==7).update({"title":"修改之后的标题"})
mySession.commit()