把MySQL表结构映射为Python中的对象的教程-Python Tutorial-php.cn

把MySQL表结构映射为Python中的对象的教程

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Release： 2016-06-10 15:16:08

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ORM

mysql的表结构是二维表，用python的数据结构表示出来就是一个列表，每一个记录是一个tuple。如下所示：

[('1', ''huangyi),('2', ''letian),('3', 'xiaosi')]

这一行并不便于看出表的结构，可以把它换成对象的形式。

class User(object):
  def __init__(self, id, name):
    self.id = id
    self.name = name

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得到：

[ 
User('1', 'huangyi'),
 
User('2', 'letian'),
 
User('3', 'xiaosi')
]

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这就是ORM(Object-relational Mapping)，把关系数据库的表结构映射到对象上。我们可以用SQLAlchemy框架来进行映射。
SQLAlchemy

#!/usr/bin/env python
#-*-coding:utf-8 -*-
 
from sqlalchemy import Column, String, create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
 
Base = declarative_base()
 
class User(Base):
  __tablename__ = 'user'
  id = Column(String(20), primary_key=True)
  name = Column(String(20))
 
engine = create_engine('mysql+mysqlconnector://root:XXXXX@localhost:3306/TUZHI')
DBSession = sessionmaker(bind=engine)
 
session = DBSession()
new_user = User(id='4', name='Huangyi')
session.add(new_user)
session.commit()
#session.close()
 
##进行查询
#session = DBSession()
user = session.query(User).filter(User.id=='4').one()
print 'type:', type(user)
print 'name:', user.name
session.close()

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Related labels：

python sqlalchemy

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