also look into the SelectResults extension which will do the somelist[90] == "SELECT ... OFFSET 90 LIMIT 1" thing. its in the "plugins" section of the docs.
On Feb 13, 4:05 pm, "Gary Bernhardt" <[EMAIL PROTECTED]> wrote: > The "Working with Large Collections" section in the advanced mapping docs is > probably what you > want:http://www.sqlalchemy.org/docs/adv_datamapping.myt#advdatamapping_pro... > > On 2/13/07, Cristiano Paris <[EMAIL PROTECTED]> wrote: > > > > > I everyone. I'm pretty new to SQLAlchemy and never done much sql-related > > work in the past as well so this could possibly be a silly question. > > > Suppose I've a table with a huge number of records. Now, I'd like to > > access this table randomly through a list-like interface of a Python > > class instance, i.e. saying foo[90] would return the 90th row of the > > table. > > > I know how to accomplish this in play MySQL's SQL, maybe using a LIMIT > > clause in the select. This way it'd be trivial to write a container > > class implementing the __getitem__() method with a a SELECT/LIMIT > > statement. > > > In addition, suppose that the SELECT statement contains a WHERE clause > > defined at foo instance's creation time (possibly through its > > constructor). Again, I'd simply plug the WHERE clause in the SELECT > > statement on every __getitem()__ invocation. > > > I think it's be possible to implement such a beast through SQLAlchemy's > > API and I thought that Query's select() method of a mapper worked that > > way, but it seems that it fetches every and each row from the DB just > > before returning a list of the mapped object instances. > > > Am I wrong? Is there a way/class in the SA's API to have sort of a lazy > > list of results of a query from which to pick randomly? > > > Thank you, > > > Cristiano --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
