python通过elixir包操作mysql数据库实例代码

yipeiwu_com6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环境下搭建属于自己的pip源的教程

一、安装pip2pi工具: pip install pip2pi 或: git clone https://github.com/wolever/pip2pi cd pip2...

pandas基于时间序列的固定时间间隔求均值的方法

pandas基于时间序列的固定时间间隔求均值的方法

如果index是时间序列就不用转datetime;但是如果时间序列是表中的某一列,可以把这一列设为index 例如: 代码: DF=df2.set_index(df1['time_...

解决python3中自定义wsgi函数,make_server函数报错的问题

#coding:utf-8 from wsgiref.simple_server import make_server def RunServer(environ, start_...

Python画图实现同一结点多个柱状图的示例

Python画图实现同一结点多个柱状图的示例

如下所示: import numpy as np x = [1,2] #横坐标 y = [3,4] #第一个纵坐标 y1 = [5,6] #第二个纵坐标 x = np.aran...

python实现关键词提取的示例讲解

新人小菜鸟又来写博客啦!!!没人表示不开心~~(>_<)~~ 今天我来弄一个简单的关键词提取的代码 文章内容关键词的提取分为三大步: (1) 分词 (2) 去停用词 (...