I am developing a library to do Active Record style validations on SA declarative instances:
http://bitbucket.org/rsyring/sqlalchemy-validation/src/tip/savalidation/ I know there are differences of opinion on the value of doing validation like this, but I am really hoping to avoid that discussion as I think it will be a valuable addition if I can get it implemented correctly. I am running into an issue with getting my hooks in the right place. I would like to be able to do the following: * I would like default values to have been applied to the instance if applicable before validation, i.e. i want to see the instance as a mirror of what the flushed SQL will look like * I would like to be able to have multiple models fail validation i.e. I want to get details on as many errors as possible before raising an exception I was initially using before_insert and before_update on the mapper extension and trying to "catch" the errors on those instances in the session extension. However, before_flush() gets called before the mapper extension's before_insert/update, so that didn't work. So, Ideally, my work flow would look something like: - before_insert/before_update called on each instance -- instance.do_validation() called; any errors are stored on the instance and the process continues - I loop through the session looking for instances with validation errors -- if I find any, I throw a ValidationError exception - SQL is actually flushed to the DB I really am in over my head a bit in SA internals though, so feel free to let me know if I am missing the big picture. -- 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.
