from sqlalchemy import create_engine, MetaData, Table
from sqlalchemy.orm import mapper, sessionmaker
from sqlalchemy.sql import select

from project.config import settings


class Persona(object):
    pass


engine = create_engine(settings.database_url)
metadata = MetaData(engine)
Session = sessionmaker(engine)
session = Session()

tabla_persona = Table('tb_personas', metadata, autoload=True)
mapper(Persona, tabla_persona)

print(tabla_persona.columns)

# Ejecutar una query
if __name__ == '__main__':
    conn = engine.connect()
    s = select([Persona.Apellido]).where(Persona.id == 802)
    res = conn.execute(s)
    row = res.fetchone()
    res = None if row is None else row['ColumnName']
    print(res)