add sqlalchemy sample

Author: michaelliao

py3/db/do_sqlalchemy.py

@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from sqlalchemy import Column, String, create_engine
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.ext.declarative import declarative_base
+
+# 创建对象的基类:
+Base = declarative_base()
+
+# 定义User对象:
+class User(Base):
+    # 表的名字:
+    __tablename__ = 'user'
+
+    # 表的结构:
+    id = Column(String(20), primary_key=True)
+    name = Column(String(20))
+
+# 初始化数据库连接:
+engine = create_engine('mysql+mysqlconnector://root:password@localhost:3306/test')
+# 创建DBSession类型:
+DBSession = sessionmaker(bind=engine)
+
+# 创建session对象:
+session = DBSession()
+# 创建新User对象:
+new_user = User(id='5', name='Bob')
+# 添加到session:
+session.add(new_user)
+# 提交即保存到数据库:
+session.commit()
+# 关闭session:
+session.close()
+
+# 创建Session:
+session = DBSession()
+# 创建Query查询，filter是where条件，最后调用one()返回唯一行，如果调用all()则返回所有行:
+user = session.query(User).filter(User.id=='5').one()
+# 打印类型和对象的name属性:
+print('type:', type(user))
+print('name:', user.name)
+# 关闭Session:
+session.close()