On 3/14/06, James Bennett <[EMAIL PROTECTED]> wrote: > > On 3/13/06, limodou <[EMAIL PROTECTED]> wrote: > > Maybe or maybe not. What django has implemented is exactly as what I > > said, I think the ways is good. And I remember there was a discussion > > about js invalidation, why we need this. Because we want to make > > mistakes can be found early, but not until the data will be saved. > > As I see it, the question here is which of two options we want to take: > > 1. Validation is performed when you try to save an object; if > validation fails, you send back some error messages and try again with > corrected data. > > 2. One or more extra layers are placed between data entry and saving > the object; different layers do different types of validation, and any > one of them can kick you back out to the data-entry layer. > > Option 1 is what we seem to be heading toward with validation-aware > models, and I think it's good for a couple of reasons: > > * It's conceptually simpler; instead of worrying about which > validation layer you got down to before an error occurred, you only > have to worry about two states: success and failure. > > * It's more logical; I still don't see any good reason why information > about how to validate an instance of a model shouldn't be part of the > model. > > * It's better from an end-user standpoint; to see why, imagine that > instead we have a system with multiple layers which do validation. In > this case, an end user creating or editing an object may make a > mistake in entering the data, and be presented with a set of errors. > He corrects them and tries again to submit the data, but this time it > comes back with a different set of errors that have been present all > along, but were never reported because the data never made it to the > layer that would have caught them before. This poor user would become, > understandably, frustrated that he wasn't told about these errors the > first time he tried to submit the data. When validation is all in the > same place, this will never be a problem because all errors will be > caught and reported each time the data is submitted. > >
Reasons sound very reasonable. But I think current implement in django is enough. Maybe model with validation is better but unnecessary. We have many ways to validate data before it saved in db. -- I like python! My Blog: http://www.donews.net/limodou NewEdit Maillist: http://groups.google.com/group/NewEdit --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django developers" group. To post to this group, send email to django-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-developers -~----------~----~----~----~------~----~------~--~---