python通过elixir包操作mysql数据库实例代码

yipeiwu_com7年前Python基础

本文研究的主要是python通过elixir包操作mysql数据库的相关实例,具体如下。

python操作数据库有很多方法,下面介绍elixir来操作数据库。elixir是对sqlalchemy lib的一个封装,classes和tables是一一对应的,能够一步定义classes,tables和mappers,支持定义多个primary key。

定义model.py

from elixir import sqlalchemy 
from elixir import * 
 
engine =sqlalchemy.create_engine('mysql://root:root@localhost/') #the first root is the user, and the sencond root is the password 
#engine.execute("DROP DATABASE IF EXISTS elixir") 
engine.execute("CREATE DATABASE IF NOT EXISTS elixir") 
 
 
metadata.bind='mysql://root:root@localhost:3306/elixir' 
#metadata.bind.echo =True 
class Movie(Entity): 
  using_options(tablename='movies') 
 
  title = Field(Unicode(30),primary_key = True) 
  year = Field(Integer, primary_key = True) 
  description = Field(UnicodeText) 
  director = ManyToOne('Director') 
  genres = ManyToMany('Genre') 
  actor = ManyToMany('Actor') 
 
  def __repr__(self): 
    return '<Move "%s" (%d)>' % (self.title, self.year) 
 
class Person(Entity): 
  using_options(inheritance='multi') 
  using_options(tablename='person') 
 
  name = Field(Unicode(60)) 
 
  def __repr__(self): 
    return '<Person "%s">' % self.name 
 
 
class Director(Person): 
  using_options(inheritance='multi') 
  using_options(tablename='director') 
 
  movies = OneToMany('Movie') 
 
  def __repr__(self): 
    return '<Director "%s">' % self.name 
 
class Genre(Person): 
  using_options(inheritance='multi') 
  using_options(tablename='genre') 
 
  movies = ManyToMany('Movie') 
 
  def __repr__(self): 
    return '<Genre "%s">' % self.name 
 
class Actor(Person): 
  using_options(inheritance='multi') 
  using_options(tablename='actor') 
 
  movies = ManyToMany('Movie') 
 
  def __repr__(self): 
    return '<Actor "%s">' % self.name 

model_test.py

from model import * 
 
# setup_all(True) is equal to the following two staps: 
setup_all() # create sqlalchemy table object as mapper object for the class 
create_all() # take all table objcts and create real tables by issuing SQL statements on the databse. 
 
Actor1 = Actor(name=u"lvliang") 
scifi = Genre(name = u"Science-Fiction") 
rscott = Director(name = u"Ridley Scott") 
glucas = Director(name = u"George Lucas") 
alien = Movie(title = u"Alien", year = 1979, director=rscott, genres=[scifi, Genre(name=u"Horror")], actor = [Actor1]) 
brunner = Movie(title = u"Blade Runner", year = 1982, director = rscott, genres=[scifi]) 
swars = Movie(title = u"Star Wars", year = 1977, director = glucas, genres=[scifi]) 
session.commit() 
 
 
m1 = Movie.query.filter_by(title=u"Alien").one() 
m2 = Movie.query.filter(Movie.year>1980).all() 
m3 = Movie.query.filter(Movie.director.has(name = u"Ridley Scott")).all() 
m4 = Movie.query.filter(Movie.director.has(Director.name.endswith(u"Scott"))).all() 
m5 = Movie.query.filter(Movie.genres.any(name = u"Horror")).all() 
 
print m1 
print m2 
print m3 
print m4 
print m5 
 
d = Director.get_by(name = u"Ridley Scott") # Class.get_by(xxx) is a shortcut for Class.query.filter_by(xxx).first 
q = Movie.query.filter_by(director = d) #get all movies directed by director d 
m = q.filter_by(year = 1979).all() 
print "Movie direct by %s in year 1979 are " %(d.name) 
print m 
 
movies = q.order_by(sqlalchemy.desc(Movie.year)).all() 
print movies 
fro m in movies: 
  m.delete() 
session.commit() 

执行model.py,结果为:

查看数据库,结果为:

总结

以上就是本文关于python通过elixir包操作mysql数据库实例代码的全部内容,希望对大家有所帮助。感兴趣的朋友可以继续参阅本站其他相关专题,如有不足之处,欢迎留言指出。感谢朋友们对本站的支持!

相关文章

python实现多人聊天室

本文实例为大家分享了python实现多人聊天室的具体代码,供大家参考,具体内容如下 一、目的 以实现小项目的方式,来巩固之前学过的Python基本语法以及相关的知识。  二、相...

用python写的一个wordpress的采集程序

用python写的一个wordpress的采集程序

在学习python的过程中,经过不断的尝试及努力,终于完成了第一个像样的python程序,虽然还有很多需要优化的地方,但是目前基本上实现了我所要求的功能,先贴一下程序代码: 具体代码如...

pytorch多进程加速及代码优化方法

目标:优化代码,利用多进程,进行近实时预处理、网络预测及后处理: 本人尝试了pytorch的multiprocessing,进行多进程同步处理以上任务。 from torch.mul...

python中使用psutil查看内存占用的情况

有的时候需要对python程序内存占用进行监控,这个时候可以用到psutil库,Anaconda中是自带的,如果import出错,可以用pip install psutil(安装在pyt...

Python pygorithm模块用法示例【常见算法测试】

本文实例讲述了Python pygorithm模块用法。分享给大家供大家参考,具体如下: pygorithm:一个用纯粹python编写的Python模块,用于纯粹的教育目的。只需导入所...