SQLAlchemy quick start

sqlalchemy_app.py

# http://bytefish.de/blog/first_steps_with_sqlalchemy/

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine
from datetime import datetime, timedelta
from sqlalchemy import Table, Column, Integer, String, DateTime, ForeignKey
from sqlalchemy.orm import relationship, backref
from sqlalchemy.orm import sessionmaker

Base = declarative_base()

class Tag(Base):

    __tablename__ = 'tags'

    id      =   Column(Integer, primary_key=True)
    name    =   Column(String(255), unique=True, nullable=False)
    
    def __repr__(self):
        return "<Tag (name='%s')>" % (self.name)

# connection
engine = create_engine('postgresql://postgres:mysecretpassword@localhost:5432/db01')

# create metadata
Base.metadata.create_all(engine)

# create session
Session = sessionmaker(bind=engine)
session = Session()

# insert data
tag_cool = Tag(name='cool')
tag_car = Tag(name='car')
tag_animal = Tag(name='animal')

session.add_all([tag_animal, tag_car, tag_cool])
session.commit()

# query data
t1 = session.query(Tag).filter(Tag.name == 'cool').first()

# update entity
t1.name = 'cool-up'
session.commit()

# delete
session.delete(t1)
session.commit()