138.python内置模块sqlalchemy进行sql操作详解

sqlalchemy官方

安装

pip3 install sqlalchemy

使用

参数解释

1. 创建一个引擎，目的是连接到我们的数据库上
   root: mysql 用户名
   password: 密码
   host: 主机ip
   dataBaseName: 数据库名字

create_engine('mysql+pymysql://root:password@host:3306/dataBaseName',echo=True)

2. 打开数据库的连接会话

session = sessionmaker(engine)

3. 保证线程安全

db_session = scoped_session(session)

4. 获取基类

Base = declarative_base()

详解demo

我的user表

连接我的数据库

import hashlib
import json
from sqlalchemy import create_engine, Column, Integer, String, Table, func
from sqlalchemy.orm import sessionmaker, scoped_session, declarative_base
from sqlalchemy import or_
from sqlalchemy.sql.elements import and_

# 创建一个引擎，目的是连接到我们的数据库上
engine = create_engine('mysql+pymysql://root:lh334421@127.0.0.1:3306/myDataBase',echo=True)
# 打开数据库的连接会话
session = sessionmaker(engine)
# 保证线程安全
db_session = scoped_session(session)
# 获取基类
Base = declarative_base()

表链接

class User(Base):
    __table__ = Table("user",Base.metadata,autoload_with=engine)

查询

1. 查询所有

result01 =  db_session.query(User).all()
print(result01)

2. 查询判断( < > = or and like limit sum )

result = db_session.query(User).filter(User.user_id < 10).all()

result = db_session.query(User).filter(User.user_id > 10).all()

result = db_session.query(User).filter(User.user_id > 10).limit(10).all()

result = db_session.query(User).filter(User.user_id > 10).limit(10).offset(2).all()

result = db_session.query(User).filter(or_(User.user_id == 1, User.user_id == 2)).all()

result = db_session.query(User).filter(and(User.user_id == 1, User.username == '1@qq.com')).all()

result = db_session.query(func.sum(User.user_id)).all()

result = db_session.query(User).order_by(User.user_id.desc()).all()

result = db_session.query(User).order_by(User.username.like("%@qq.com")).all()

删除

result = db_session.query(User).filter(User.user_id == 1).delete()

增加

params = {
   "username": '"张三",
   "nickname": “zs”,
   "password": 123,
   "picture": “1.png”,
}
user = User(**params)
db_session.add(user)
db_session.commit()