On Sunday 02 July 2006 18:11, you wrote: > On Jul 2, 2006, at 4:05 AM, Tzahi Fadida wrote: > > Finally, when operations are done on a session. when i do > > session.flush() are > > they guaranteed to be performed in order? at least when i use > > transactions. > > 10x. > > when a flush() occurs, if you havent started a transaction yourself, > a transaction will be used internally to enclose all statements > issued by the flush(). > > statements will be in order of table dependency first; i.e. sorted > based on the foreign key dependencies between either tables or > individual rows in the case of self-referential mappers. this > means if table B contains a foreign key relationship to table A, > table A's rows will always be inserted/updated first before that of > table B, and table A's rows will be deleted after all changes on > table B are complete. > > if a table A references itself, then the rows will be inserted/ > updated based on the foreign key dependency of individual rows in > table A. > > For rows within a table that dont have foreign key dependencies to > each other, rows will be INSERTED based on the order the objects were > added to the Session, or if they are part of a list-based collection > on another object they will be inserted in the order of that collection. > > For UPDATES and DELETES of non-dependent rows within the same table, > the ordering is generally consistent but I wouldnt say its > "guaranteed" at this point since there are some Sets in use to store > "dirty" and "deleted" objects in the session; I have a feeling i > would need to patch the "dirty" and "deleted" Set objects in > unitofwork.py to be OrderedSets and that would probably do it > (although i wouldnt feel confident unless i could come up with some > unittests to test that; which is tricky because Python tends to > order even unordered dictionaries similarly within a single run and > even across multiple runs. it might require hacking dict to return > items in an explicitly randomized order to insure no dict-based > ordering is in use). > > you should experiment with some test and example programs and have > echo=True on to get a feel for the behavior of flush().
I am a little confused about your answer. My main concern though, is that the result of the implicit and explicit transactions to the database will be the same as if i executed flush() after each query/insert/delete. I.e. this seems a little non-deterministic, isn't that risky? 10x. -- Regards, Tzahi. -- Tzahi Fadida Blog: http://tzahi.blogsite.org | Home Site: http://tzahi.webhop.info WARNING TO SPAMMERS: see at http://members.lycos.co.uk/my2nis/spamwarning.html Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Sqlalchemy-users mailing list Sqlalchemy-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/sqlalchemy-users
