insert() has had some inconsistencies being reported as of late (like params() ) that i would like to get nailed down. a construct like this shouldn't have any surprises.
On Nov 26, 2008, at 6:04 PM, MikeCo wrote: > > And that is what we did in our application before this discussion even > started. Don't know what Petr is doing in his. > I think it is more of an interesting, mostly academic, discussion > about alternative techniques; probably a very low priority issue to > the SA code base. > > > On Nov 26, 5:56 pm, Michael Bayer <[EMAIL PROTECTED]> wrote: >> executemany() syntax is very efficient and I dont really understand >> how the column/string thing is that much of an issue other than an >> small inconvenience and a slight failure of the API to be >> consistent...all you have to do is convert the dict keys to be >> column.key. >> >> On Nov 26, 2008, at 5:52 PM, MikeCo wrote: >> >> >> >>> Oops, I stand corrected. seehttp://pastebin.com/fe4a38d6 >> >>> At least for SQLite, my loop solution is many times slower than the >>> insert many syntax. I would be curious to see results run against >>> different database engines. I don't have quick access to them right >>> now. >>> Still, unless there are very large numbers of inserts there should >>> be >>> little, if any, noticeable difference. >> >>> -- >>> Mike >> >>> On Nov 26, 4:50 pm, MikeCo <[EMAIL PROTECTED]> wrote: >>>> You probably don't want to do the inserts one by one because of the >>>> commit overhead, or needing to rollback on failure of on insert. >>>> You >>>> can still get multiple inserts in one transaction. Add this to the >>>> example posted athttp://pastebin.com/fd0653b0tosee three inserts in >>>> one transaction. >> >>>> print '****', '5. column attributes in .values()' >>>> data = [{MyTable.c.col1:itm.x} for itm in items] >>>> print '****', data >>>> trans = conn.begin() # < - - start a transaction to wrap many >>>> inserts >>>> for d in data: >>>> conn.execute(MyTable.insert().values(d)) >>>> trans.commit() # < - - end transaction >> >>>> Wrapping the insert loop in a transaction should give you the >>>> same or >>>> very nearly the same performance as executing the "insert many" >>>> operation, and only adds 4 or 5 simple lines of code. The exception >>>> might be if you have a large batch process inserting thousands or >>>> tens >>>> of thousands of records; in that case, you will need to design a >>>> solid >>>> commit strategy anyway. with or without SQLAlchemy. >> >>>> -- >>>> Mike >> >>>> On Nov 26, 10:42 am, "Michael Bayer" <[EMAIL PROTECTED]> >>>> wrote: >> >>>>> Petr Kobalíèek wrote: >> >>>>>> So, I can use that way in inserting one row, but can't when >>>>>> inserting >>>>>> multiple rows ? It is correct ? >> >>>>> you can only use string keys as the arguments to the execute() >>>>> method. >>>>> this applies to one row or many. columns as keys can be used for >>>>> the >>>>> values argument/generative method on an insert() or update() >>>>> construct. >> >>>>> to be quite honest there was never an intention for columns as >>>>> keys to not >>>>> work properly when sent as keys as parameters to .execute(), there >>>>> just >>>>> seems to be a lack of testing in this case, so feel free to file a >>>>> ticket >>>>> for this. > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com 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 -~----------~----~----~----~------~----~------~--~---
