On Apr 3, 2008, at 1:43 PM, jason kirtland wrote:
> > Yannick Gingras wrote: >> >> Hi, I use Alchemy to connection to a legacy system from which I pull >> data to be inserter into a new system that is being built with >> Python. >> >> I'm only interested by a tiny fraction of the legacy data and I'm >> wondering if it's possible to specify constraints to the mapper do >> that >> >> Obj.query() >> >> would only fetch rows with col_a == foo and col_b == bar. >> >> I know how to do that for a field of the object with >> >> relation(..., primary_join=...) >> >> How would I do that at the object level? > > A couple approaches come to mind: > - map Obj to a select() with the restrictions baked in > - use Query(obj).select_from() with a restrictive select > > Making a custom Obj.query property that puts select_from on the > query by > default is pretty easy too. you can also set up the Mapper in the first place to use a subset of columns using the "include_properties" and "exclude_properties" arguments. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
