models.py

from sqlalchemy import (create_engine, Column, Integer, String, ForeignKey)
from sqlalchemy.orm import (scoped_session, sessionmaker, relationship)
from sqlalchemy.ext.declarative import declarative_base

engine = create_engine('sqlite:///atividades.db')
db_session = scoped_session(sessionmaker(autocmmit=True,
                                         bind=engine))

Base = declarative_base()
Base.query = db_session.query_property()


class Pessoas(Base):
    __tablename__ = 'pessoas'
    id = Column(Integer, primary_key=True)
    nome = Column(String(40), index=True)
    idade = Column(Integer)

    def __repr__(self):
        return '<Pessoa {}>'.format((self.nome))

    def save(self):
        db_session.add(self)
        db_session.commit()

    def delete(self):
        db_session.delete(self)
        db_session.commit()


class Atividades(Base):
    __tablename__ = 'atividades'
    id = Column(Integer, primary_key=True)
    nome = Column(String(80))
    pessoa_id = Column(Integer, ForeignKey('pessoas.id'))
    pessoa = relationship("Pessoas")

    def __repr__(self):
        return '<Atividades {}>'.format((self.nome))

    def save(self):
        db_session.add(self)
        db_session.commit()

    def delete(self):
        db_session.delete(self)
        db_session.commit()


class Usuarios(Base):
    __tablename__ = 'usuarios'
    id = Column(Integer, primary_key=True)
    login = Column(String(20), unique=True)
    senha = Column(String(20))

    def __repr__(self):
        return '<Usuario {}>'.format(self.login)

    def save(self):
        db_session.add(self)
        db_session.commit()

    def delete(self):
        db_session.delete(self)
        db_session.commit()


def init_db():
    Base.metadata.create_all(bind=engine)


if __name__ == '__main__':
    init_db()