On Jul 16, 2007, at 1:58 PM, [EMAIL PROTECTED] wrote:
> Storing just the base-most class would solve some (speed) issues, but > others will remain - for each Class u'll have to do > 1 get mapper for the Class > 2 find the Base - the base-most mapper - or first concrete one > towards root > 3 constitute identity key from that and look it up. > so it's 2 lookups + a hierarchy descent to the base. for what operation, a get() ? if you have Person->(Employee, Manager, Engineer, ...) the mapper.identity_key_from_instance() function will return (Person, (id,)) for all of those classes. i.e. each class_mapper() will know what to do, and we wont even have the keys with the subclasses anymore. > > As for concrete-ism, while doing/supporting mixed inheritance in > principle i found that concrete-table things behave like > offsetted "roots", i.e. all things start a new from them. (sawrap: > that's in make_klas_selectable() func + the big comment after it, as > well in the as make_mapper ). yes, if you have Person->Employee via joined, they both get a (Person, (id,)) id. but if Manager is concrete, it gets (Manager, (id,)). --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
