sqlalchemy练习（一）

# -*- coding: utf-8 -*-
# @Time    : 2017/4/10 10:08
# @Author  : xiaojingjing
# @File    : sqlalchemy_tutorial.py
# @Software: PyCharm
import sqlalchemy
#引入此包，方便告诉程序使用什么数据库引擎
from sqlalchemy import create_engine
#根据不同数据库引擎创建一个基类,然后通过集成创建这个表对应的类
from sqlalchemy.ext.declarative import declarative_base
#导入创建类时对应类型的定义
from sqlalchemy import Column,Integer,String
#导入事务处理函数
from sqlalchemy.orm import sessionmaker
#关系操作查询模块
from sqlalchemy import and_,or_




#查看SQLAlchemy当前版本
print(sqlalchemy.__version__)


#创建数据库引擎，这里拿的小型数据库sqlite"'sqlite:///foo.db'"sqlite数据库引擎在create_engine中的参数配置 ； "echo=True"表示数据库操作的原始语句将会被显示出来
engine=create_engine('sqlite:///foo.db',echo=True)

Base=declarative_base()
class User(Base):
    __tablename__='user_login'

    id=Column(Integer,primary_key=True)
    username=Column(String(30))
    password=Column(String(30))

    def __repr__(self):
        return "<User(name='%s',password='%s')>"%(self.username,self.password)

#创建表
# Base.metadata.create_all(engine)

# #插入数据
# ad_user=User(username='one',password='onlyone')
# print(ad_user)

#创建事务，并实例化

Session=sessionmaker(bind=engine)
session=Session()
# session.add(ad_user)

#添加一条查询语句
our_users=session.query(User).filter_by(username='one').first()

#批量添加
# session.add_all(
#     [
#         User(username='two',password='onlytwo'),
#         User(username='three',password='onlythree'),
#         User(username='four',password='onlyfour'),
#         User(username='five',password='onlyfive')
#
#     ])
#
# #提交事务
# session.commit()

#查询一条数据,指定username=two，查询第一条，first()默认为第一条，first(10)为前10条
# print(session.query(User).filter_by(username='two').first())

#查询所有,User为对象，对象里面指定了表名"user_login"
# print(session.query(User).all())

#根据id查询循环打印
# for row in session.query(User).order_by(User.id):
#     print(row)

#查找username为（'one','two','three'）的数据~in
# for row in session.query(User).filter(User.username.in_(['one','two','three'])):
#     print(row)

#查找username不为（'one','two','three'）的数据~not in
# for row in session.query(User).filter(~User.username.in_(['one','two','three'])):
#     print(row)

#统计数量,username为“one”的数量
# count=session.query(User).filter(User.username=='one').count()
# print(count)

#And条件判断
# for row in session.query(User).filter(and_(User.username=='one',User.password=='onlyone')):
#     print(row)

#Or条件判断
# for row in session.query(User).filter(or_(User.username=='one',User.username=='two')):
#     print(row)

#创建带有外键的表
from sqlalchemy import ForeignKey
from sqlalchemy.orm import relationship,backref

class Address(Base):
    __tablename__='addresses'
    id=Column(Integer,primary_key=True)
    email_address=Column(String,nullable=False)
    user_id=Column(Integer,ForeignKey('user_login.id'))

    user=relationship("User",backref=backref('addresses',order_by=id))

    def __repr__(self):
        return "<Address(email_address='%s')>"%self.email_address

#执行创建操作
# Base.metadata.create_all(engine)


#对两张表添加数据，并根据外键查询结果
jack=User(username='jack',password='admin')
jack.addresses=[
    Address(email_address='jack@yeah.net'),
    Address(email_address='towjd@sina.com')]
session.add(jack)
session.commit()

for u,a in session.query(User,Address).\
    filter(User.id==Address.user_id).\
    filter(Address.email_address=='jack@yeah.net').\
    all():
    print(u,a)