My examples was faulty. Sorry. I meant after you save the object for the first time, that is:
obj = Product(name='Apple') obj.save() At this point obj has an ID in it. How does it know that ID? A SQL statement similar to the following must be generated: insert into product_table (id, name) values(next_sequence, 'Apple'); But that SQL statement doesn't return its generated ID. Is it that Django first gets the next ID in sequence and then uses it in insert or it retrieves it in a different way. As Alex mentioned above, if there is a select statement, what could it be? (Select id from product_table where name='Apple') doesn't seem plausible. Once again, I have an AFTER trigger that sets my PKs from a different table and need to understand how django does it, so I can understand how to approach my own problem, Thanks again, Sia On Sep 23, 5:58 pm, Richard Dahl <[EMAIL PROTECTED]> wrote: > Actually, > from the db-api documentation. > > "To create an object, instantiate it using keyword arguments to the > model class, then call save() to save it to the database. ... > > ... Django doesn't hit the database until you explicitly call save()." > > The code: > obj = Product(name='Apple') > > obj.id will not be set until you either explicitly set it, or call > save(), at which time django will utilize the lack of a pk (among > other things) to determine whether or not to do an insert or update. > > -richard > > On Sep 23, 2007, at 9:38 AM, Alex Koshelev wrote: > > > > > I think that when you create Product object django inserts new row > > into database and retrieves with SELECT new id. > > > On 23 сент, 16:00, Siah <[EMAIL PROTECTED]> wrote: > >> Hi, > > >> When in a model you run something like this: > > >>>> obj = Product(name='Apple') > >>>> obj.id > > >> 4 > > >> I realize the first statement will turn into an insert table. But, > >> how > >> does django know of its newly assigned primary key(ID). > > >> I have a legacy database whose ID is assigned with an after trigger, > >> and am trying to understand how I can integrate them. > > >> Thanks, > >> Sia --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" 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/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
