Sqlalchemy sqlの錬金術

Transcript

• 1. SQLAlchemy SQLの錬金術 Plone Symposym Tokyo 2015 aodag
• 2. 「Who Are You?」 Atsushi Odagiri Use Python from 2001 Work at Be Proud, Inc.
• 3. What is SQLAlchemy? Python Library for Data Accessing to RDBMS. That has SQL Expression and OR Mapper.
• 4. Why I use SQLAlchemy I Don’t Know Other OR Mapper with Python. I Love SQL And Python! SQLAlchemy has SQL Expression That makes SQL Python Object. SQLAlchemy doesn’t keep me away from SQL.
• 5. SQLAlchemy features SQL Expression Object-Relational Mapper Unit of Work
• 6. SQL Expression(schema) users = Table(“users”, metadata, Column(‘id’, Integer, primary_key=True), Column(‘first_name’, Unicode(255)), Column(‘last_name’, Unicode(255)), Column(‘company_id’, Integer, ForeignKey(‘company.id’)))
• 7. SQL Expression (Insert) users.insert().values( first_name=u”Atsushi”, last_name=u”Odagiri”, )
• 8. SQL Expression(Select) select([users]).where( users.c.first_name==u’Atsushi’, )
• 9. OR Mapper class User(object): def __init__(self, first_name, last_name): self.first_name = first_name self.last_name = last_name @property def full_name(self): return self.first_name + self.last_name
• 10. OR Mapper mapper(User, users) user = Session.query(User).filter( User.first_name == u’Atsushi’).first() user.first_name = u’aodag’ Session.flush()
• 11. Unit Of Work There are no save method. Session object manages Object states. That calls DML depending on the object state.
• 12. Unit Of Work user = User(u’Atsushi’, u’Odagiri’) Session.add(user) user.company = Company(u’BeProud’) Session.flush() user.first_name = u’aodag’ Session.flush()
• 13. Getting Started Install Declare Models Connect Create Table Query Model Use Session
• 14. Install SQLAlchemy pip install sqlalchemy option:: Database Drivers pip install psycopg2 pip install mysql-python ...
• 15. Declare Models (DataType) from sqlalchemy import ( Colum, Unicode, Integer, DateTime, ForeignKey, )
• 16. Declare Models (ORM) from sqlalchemy.orm import ( relationship, ) from sqlalchemy.ext.declarative import ( delcarative_base, )
• 17. Declare Models (class) Base = declarative_base() class User(Base): __tablename__ = ‘users’ ...
• 18. Declare Models (Property) id = Column(Integer, primary_key=True) first_name = Column(Unicode(255)) last_name = Column(Unicode(255))
• 19. hybrid property from sqlalchemy.ext.hybrid import ( hybrid_property, )
• 20. @hybrid_property def full_name(self): return (self.first_name + “ “ + self.last_name)
• 21. Connect engine = create_engine(‘sqlite:///’) connection url postgresql://user:password@localhost/db mysql+pymysql://user: password@localhost/db
• 22. Create Table Base.meatadata.create_all(bind=engine)
• 23. Query Model from sqlalchemy.orm import ( scoped_session, sessionmaker, ) Session = scoped_session(sessionmaker()) Session.configure(bind=engine)
• 24. Query Model aodag = Session.query(User).filter( User.full_name == u’Atsushi Odagiri’ ).one()
• 25. Session And Transaction Session.remove() Session.add(user) Session.flush() Session.commit()
• 26. With Web Application Transaction Manager With zope.sqlalchemy ● repoze.tm2 ● pyramid_tm ● Zope2 transaction
• 27. With Web Application Transaction WSGI Middleware @wsgify.middleware def transaction_middleware(app, req, session): try: return req.get_response(app) except: session.rollback() else: session.commit()
• 28. With asyncio/aiopg @async.coroutine def get(): with (yeild from engine) as con: res = yeild from con.execute( select([users]).where( users.c.first_name == u’Atsushi’)
• 29. Conclusion SQLAlchemy has many features. SQLAlchemy supports many kind of SQL Statements. That’s Great!
• 30. Bib. ● http://www.sqlalchemy.org/ ● http://aiopg.readthedocs.org/ ● http://repozetm2.readthedocs.org/ ● https://pypi.python.org/pypi/zope. sqlalchemy ● PEP 0249 -- Python Database API Specification v2.0
• 31. That’s all