Python uses the elixir package to operate mysql database instance code, elixirmysql

Python uses the elixir package to operate mysql database instance code, elixirmysql

This article mainly describes how to use the elixir package to operate mysql database in python.

There are many methods to operate a database using python. The following describes how to operate a database using elixir. Elixir is an encapsulation of sqlalchemy lib. The classes and tables correspond one to one. It can define classes, tables, and mappers in one step, and supports defining multiple primary keys.

Define 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() 

Run model. py and the result is:

View the database. The result is:

Summary

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