用sqlalchemy对mysql数据库增删改查demo

    首先要搭建mysql服务器、安装mysql python驱动、安装sqlalchemy包，

    我用的是windows环境，安装参考：https://blog.csdn.net/jishuwenming/article/details/80993840

    完整demo 如下：

#!/usr/bin/python  
# -*- coding: utf-8 -*-  

from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String
from sqlalchemy.orm import sessionmaker
import unittest

HOSTNAME = "localhost"
PORT = "3306"
DATABASE = "test"
USERNAME = "root"
PASSWORD = "mysql123"

DB_URI = "mysql+mysqldb://{username}:{password}@{host}:{port}/{db}?charset=utf8".\
    format(username=USERNAME,password=PASSWORD,host=HOSTNAME,port=PORT,db=DATABASE)

#连接数据库
connect = create_engine(DB_URI)

#生成ORM基类
Base = declarative_base()  
#生成数据库表模型
class User(Base):
    __tablename__ = "user_login_table"  # 表名
    id = Column(Integer, primary_key=True)
    name = Column(String(32))
    password = Column(String(64))

#创建表结构	
def creat_table():
    Base.metadata.create_all(connect)  

#删除表结构
def rm_table():
    Base.metadata.drop_all(connect)

def creat_session():
    #创建与数据库的会话session class ,这里返回给session的是class
    session_class = sessionmaker(bind=connect)  
    #生成session实例
    return session_class()    

#增加数据
def orm_insert(name_value, password_value):
	obj = User(name = name_value, password = password_value)  #生成数据对象
	session.add(obj) #把要创建的数据对象添加到session里
	session.commit() #创建数据

#查询数据，查不到情况下异常处理
def orm_password_query(name_key):
    try:
        ret = session.query(User).filter_by(name = name_key).first().password
    except AttributeError:
        print '\n********************'
        return 1
    else:
        return ret
    finally:
        print '\n================='

#删除一条数据		
def orm_delete_by_name(name_key):
    session.query(User).filter(User.name == name_key).delete() 
    session.commit() 

#修改密码
def orm_modify_by_name(name_key, password_modify):
    session.query(User).filter(User.name == name_key).update({User.password: password_modify}, synchronize_session=False)
    session.commit() 
	
class MysqlOperationTest(unittest.TestCase):
    """Test mathfuc.py"""
    def test_orm_insert(self):
        """Test method orm_insert(a, b)"""
        orm_insert("34443", "44rfdfd")
        password = orm_password_query("34443")
        self.assertEqual("44rfdfd", password)

    def test_orm_delete(self):
        orm_delete_by_name("34443")
        password = orm_password_query("34443")
        self.assertEqual(1, password)
		
    def test_orm_modify(self):
        orm_insert("34443", "44rfdfd")
        orm_modify_by_name("34443", "fdsdsds")
        password = orm_password_query("34443")
        self.assertEqual("fdsdsds", password)

    def test_orm_query(self):
        #其实增删改操作已测试了查询,此处用例完整性
        orm_insert("ff444", "44rfdfd")
        password = orm_password_query("ff444")
        self.assertEqual("44rfdfd", password)

if __name__ == '__main__':
    rm_table()
    creat_table() 
    session = creat_session()

    suite = unittest.TestSuite()
    suite.addTest(MysqlOperationTest("test_orm_insert"))
    suite.addTest(MysqlOperationTest("test_orm_delete"))
    suite.addTest(MysqlOperationTest("test_orm_modify"))
    suite.addTest(MysqlOperationTest("test_orm_query"))
    runner = unittest.TextTestRunner(verbosity=2)
    runner.run(suite)