Thanks! пятница, 30 августа 2013 г., 17:46:47 UTC+7 пользователь Gunnlaugur Briem написал: > > The reason for the extra selects is that calling commit() marks objects in > the session as expired, so they need to be refreshed. From the ORM > tutorial <http://docs.sqlalchemy.org/en/rel_0_8/orm/tutorial.html>: > > SQLAlchemy by default refreshes data from a previous transaction the first >> time it’s accessed within a new transaction, so that the most recent state >> is available. The level of reloading is configurable as is described in >> *Using >> the Session* <http://docs.sqlalchemy.org/en/rel_0_8/orm/session.html>. > > > From the section on > committing<http://docs.sqlalchemy.org/en/rel_0_8/orm/session.html#committing> > : > > Another behavior of commit() is that by default it expires the state of >> all instances present after the commit is complete. This is so that when >> the instances are next accessed, either through attribute access or by them >> being present in a Query result set, they receive the most recent state. >> To disable this behavior, configure sessionmaker with >> expire_on_commit=False. > > > The other option, is to just commit after the loop, not inside it. That is > OK if the loop is not too long-running and there aren't tricky locking > ramifications — and indeed it may be preferable if you want to make sure > the ManagerConfigs you create are transactionally consistent with the > BarLogs they are based on; for that you might also consider loading the > BarLogs .with_lockmode('read') > > Gulli > > > > On Fri, Aug 30, 2013 at 8:10 AM, Дмитрий Косолапов > <kosol...@gmail.com<javascript:> > > wrote: > >> my program code: >> >> >> engine = create_engine(connect_str, echo=True)Session = >> sessionmaker(bind=engine)for bar in default_session.query(BarLog)[:3]: >> conf = ManagerConfig(indicator_config='', timeframe=bar.timeframe, >> paper_no=1) >> default_session.add(conf) >> default_session.commit() >> >> >> log: >> >> 2013-08-29 22:52:58,640 INFO sqlalchemy.engine.base.Engine BEGIN (implicit) >> >> 2013-08-29 22:52:58,642 INFO sqlalchemy.engine.base.Engine SELECT bar_log.id >> AS bar_log_id, bar_log.max AS bar_log_max, bar_log.min AS bar_log_min, >> bar_log.open AS bar_log_open, bar_log.close AS bar_log_close, bar_log.volume >> AS bar_log_volume, bar_log.time_start AS bar_log_time_start, bar_log.date AS >> bar_log_date, bar_log.timeframe AS bar_log_timeframe, bar_log.paper_no AS >> bar_log_paper_no >> >> FROM bar_log >> LIMIT %(param_1)s >> >> 2013-08-29 22:52:58,642 INFO sqlalchemy.engine.base.Engine {'param_1': 3} >> >> 2013-08-29 22:52:58,646 INFO sqlalchemy.engine.base.Engine INSERT INTO >> manager_config (paper_no, timeframe, indicator_config) VALUES (%(paper_no)s, >> %(timeframe)s, %(indicator_config)s) RETURNING manager_config.id >> >> 2013-08-29 22:52:58,646 INFO sqlalchemy.engine.base.Engine >> {'indicator_config': ‘', ’paper_no': 1, ‘timeframe’: 1} >> >> 2013-08-29 22:52:58,647 INFO sqlalchemy.engine.base.Engine COMMIT >> >> 2013-08-29 22:52:58,662 INFO sqlalchemy.engine.base.Engine BEGIN (implicit) >> >> 2013-08-29 22:52:58,664 INFO sqlalchemy.engine.base.Engine SELECT bar_log.id >> AS bar_log_id, bar_log.max AS bar_log_max, bar_log.min AS bar_log_min, >> bar_log.open AS bar_log_open, bar_log.close AS bar_log_close, bar_log.volume >> AS bar_log_volume, bar_log.time_start AS bar_log_time_start, bar_log.date AS >> bar_log_date, bar_log.timeframe AS bar_log_timeframe, bar_log.paper_no AS >> bar_log_paper_no >> >> FROM bar_log >> WHERE bar_log.id = %(param_1)s >> >> 2013-08-29 22:52:58,664 INFO sqlalchemy.engine.base.Engine {'param_1': 2} >> >> 2013-08-29 22:52:58,667 INFO sqlalchemy.engine.base.Engine INSERT INTO >> manager_config (paper_no, timeframe, indicator_config) VALUES (%(paper_no)s, >> %(timeframe)s, %(indicator_config)s) RETURNING manager_config.id >> >> 2013-08-29 22:52:58,668 INFO sqlalchemy.engine.base.Engine >> {'indicator_config': ‘', ’paper_no': 1, ‘timeframe’: 1} >> >> 2013-08-29 22:52:58,670 INFO sqlalchemy.engine.base.Engine COMMIT >> >> 2013-08-29 22:52:58,679 INFO sqlalchemy.engine.base.Engine BEGIN (implicit) >> >> 2013-08-29 22:52:58,681 INFO sqlalchemy.engine.base.Engine SELECT bar_log.id >> AS bar_log_id, bar_log.max AS bar_log_max, bar_log.min AS bar_log_min, >> bar_log.open AS bar_log_open, bar_log.close AS bar_log_close, bar_log.volume >> AS bar_log_volume, bar_log.time_start AS bar_log_time_start, bar_log.date AS >> bar_log_date, bar_log.timeframe AS bar_log_timeframe, bar_log.paper_no AS >> bar_log_paper_no >> >> FROM bar_log >> WHERE bar_log.id = %(param_1)s >> >> 2013-08-29 22:52:58,681 INFO sqlalchemy.engine.base.Engine {'param_1': 3} >> >> 2013-08-29 22:52:58,685 INFO sqlalchemy.engine.base.Engine INSERT INTO >> manager_config (paper_no, timeframe, indicator_config) VALUES (%(paper_no)s, >> %(timeframe)s, %(indicator_config)s) RETURNING manager_config.id >> >> 2013-08-29 22:52:58,685 INFO sqlalchemy.engine.base.Engine >> {'indicator_config': ‘', ’paper_no': 1, ‘timeframe’: 1} >> >> 2013-08-29 22:52:58,688 INFO sqlalchemy.engine.base.Engine COMMIT >> >> >> how to use one select query and many insert queries? >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sqlalchemy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to sqlalchemy+...@googlegroups.com <javascript:>. >> To post to this group, send email to sqlal...@googlegroups.com<javascript:> >> . >> Visit this group at http://groups.google.com/group/sqlalchemy. >> For more options, visit https://groups.google.com/groups/opt_out. >> > >
-- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/groups/opt_out.
