def create_records():
session = create_session()
account1 = Account(name='account1', amount=Decimal('11.11'))
account2 = Account(name='account2', amount=Decimal('22.22'))
session.add(account1)
session.add(account2)
session.commit()
def first_flow(print_function):
session = create_session()
print_function('Adding account 3...')
account3 = Account(name='account3', amount=Decimal('33.33'))
session.add(account3)
print_function('Flushing changes to the DB...')
session.flush()
print_function('Sleeping...')
sleep(5)
print_function('Waking up...')
print_function('We didn\'t commit anything...')
def first_flow(print_function):
session = create_session()
print_function('Adding account 3...')
account3 = Account(name='account3', amount=Decimal('33.33'))
session.add(account3)
print_function('Flushing changes to the DB...')
session.flush()
print_function('Sleeping...')
sleep(5)
print_function('Waking up...')
print_function('Rolling back...')
session.rollback()
print_function('Rolled back!!')
def second_flow(print_function):
session = create_session()
print_function('Adding new account at the meantime...')
account3 = Account(name='account3', amount=Decimal('33.33'))
session.add(account3)
account1 = session.query(Account).filter(Account.name == 'account1').one_or_none()
account2 = session.query(Account).filter(Account.name == 'account2').one_or_none()
if account1:
print_function('Updating existing account at the meantime...')
account1.name = 'Updated from second flow'
session.commit()
if account2:
print_function('Deleting existing account at the meantime...')
session.delete(account2)
session.commit()
print_function('Committed!!')
from sqlalchemy import create_engine from sqlalchemy.orm import sessionmaker from account_model import Account from common import print_first connecting_string = f'mysql+mysqldb://root:[email protected]:52000/lunch_and_learn' engine = create_engine(connecting_string, echo=True, connect_args={'connect_timeout': 10}) Session = sessionmaker(bind=engine, autoflush=True) session = Session() account1 = Account(name='account1', amount=Decimal('11.11')) account2 = Account(name='account2', amount=Decimal('22.22')) session.add(account1) session.add(account2) session.flush() # session.query(Account).count() print_first('Sleeping..') sleep(7) print_first('Waking up!') print_first('Committing...') session.commit() print_first('Committed')