models.py

from flask.ext.sqlalchemy import SQLAlchemy

db = SQLAlchemy()

class Cloud(db.Model):
    __tablename__ = 'cloud'

    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String, nullable=False)
    description = db.Column(db.String, nullable=False)

    def __str__(self):
        return self.name

class Machine(db.Model):
    __tablename__ = 'machine'

    id = db.Column(db.Integer, primary_key=True)
    hostname = db.Column(db.String, nullable=False)
    operating_system = db.Column(db.String, nullable=False)
    description = db.Column(db.String, nullable=False)
    cloud_id = db.Column(db.Integer, db.ForeignKey('cloud.id'))
    cloud = db.relationship('Cloud')
    is_running = db.Column(db.Boolean, default=False, nullable=False)

    def __str__(self):
        return self.hostname

runserver.py

from flask import Flask
from models import Machine, Cloud, db

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///db.sqlite3'
db.init_app(app)
with app.app_context():
    db.create_all()
app.run(debug=True)