python通过elixir包操作mysql数据库实例代码

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')  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 

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()