45 - ORM框架知多少

1. 在python语言中有哪些常用的ORM框架，它们有什么区别

• ORM(Object Ralational Mapping, 对象关系映射) 用来把对象模型表示的对象映射到基于SQL的关系型数据库结构中去
• SQLAlchemy：偏向于SQL，可以灵活地提交SQL语句
• SQLObject：更加面向对象，无法自由使用原生的SQL语句

2. 如何使用SQLObject框架操作MySQL数据库

'''
pip install sqlobject
'''
from sqlobject import *
from sqlobject.mysql import builder
import json

mysql = 'mysql://root:root@localhost:3306/db?charset=utf8'

sqlhub.processConnection = connectionForURI(mysql, driver='pymysql')

class Person(SQLObject):
    class sqlmeta:
        table = 't_persons'
    name = StringCol(length = 30)
    age = IntCol()
    address = StringCol(length = 30)
    salary = FloatCol()
    
try:
    Person.dropTable()
except:
    pass

Person.createTable()

print('create success')

# 插入记录
person1 = Person(name = 'Bill', age = 15, address = 'China', salary = 1111)
person2 = Person(name = 'Mike', age = 20, address = 'beijing', salary = 2222)
person3 = Person(name = 'John', age = 49, address = 'shanghai', salary = 3333)

print('insert success')

create success
insert success

# 修改
person2.name = 'laowang'
person2.address = 'shanghai'

# 查询数据表
persons = Person.selectBy(name = 'Bill')
print(persons[0])
print(persons[0].id)
print(persons[0].name)
print(persons[0].address)
print(persons[0].salary)

<Person 1 name='Bill' age=15 address='China' salary=1111.0>
1
Bill
China
1111.0

# 删除数据
persons[0].destroySelf()
print('del success')

del success

46 - 将xml文档保存在MongoDB数据库中