Michael On Mar 25, 12:33 pm, "Michael Bayer" <[email protected]> wrote: > nothing ever "refreshes" automatically. only things that have been > "expired", or were never loaded in the first place, are loaded when requested.
Good to know. > to reduce expirations, > readhttp://www.sqlalchemy.org/docs/session.html#committing. This is exactly what I was looking for, specifically "To disable this behavior, configure sessionmaker() with expire_on_commit=False." However, now that I did, things are more complicated, and SQLAlchemy 0.5 complains. 2010-03-25 13:19:02,049 INFO sqlalchemy.engine.base.Engine.0x...f054 BEGIN 2010-03-25 13:19:02,049 INFO sqlalchemy.engine.base.Engine.0x...f054 UPDATE xxx SET yyy=now() WHERE xxx.zzzzz = %s AND xxx.aaaaa = %s 2010-03-25 13:19:02,049 INFO sqlalchemy.engine.base.Engine.0x...f054 [193302, None] 2010-03-25 13:19:02,050 INFO sqlalchemy.engine.base.Engine.0x...f054 ROLLBACK Traceback (most recent call last): . . . File "sqlalchemy/orm/mapper.py", line 1401, in _save_obj sqlalchemy.orm.exc.ConcurrentModificationError: Updated rowcount 0 does not match number of objects updated 1 I will begin to investigate how to avoid that error. I'd appreciate any advice or hints. Also, I would like to know how I prevent SQLAlchemy from issuing BEGIN and COMMIT statements to the database. This is a MySQL database with MyISAM tables that have no transaction support. This is an overloaded, remote database, and touching it is expensive. > Also, if applicable, consider using fewer database-level defaults to populate > columns on flush - these values are necessarily read in when you request to > see them. Good to know, but this was not my specific problem. > To increase what's loaded in a single query is a more elaborate topic which > involves the specifics of the mappings you are using. Usually "eager > loading" is the first place to start. If you're using joined table > inheritance, read the mapper docs on configuring "with polymorphic". Also not my specific problem. Thanks, Keith -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
