CUSTOM_ID-----------------------ID ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INV00001 ---------------------- 1 INV00002 -----------------------2 INV00003------------------------3 . . . i think you need INV00001 for display purposes and also i hope it does not matter much whether you store 1 or INV00001 in the db.
in such cases why can't you follow the below approach? ------------------------------------------------------ store as 1 but display it as INV00001 (by appending 1 to 'INV0000') when you want to search 'INV00002' strip out the INV and convert the other part to 2 and search for this 2 in the database. ~~ I don't know whether this is feasible to you or not but just a thought adding to suggestion of "Will Hardy". On Feb 3, 4:47 am, Will Hardy <e.willha...@gmail.com> wrote: > There's no easy solution without saving the object to the database. > Auto incrementing fields (AutoField or just id) get their value from > the database, so they wont have one until you save. This is good > because it prevents multiple objects ever having the same value. One > way to do what you want is to save a new invoice to the database > straight away when the user clicks "add new invoice" and allow them to > edit it, but if you're using the admin site, this might not be > straightforward. > > You wont need to create a new field by the way, you could simply make > a property that uses the ID field of a model: > > @property > def invoice_id(self): > if self.id: > return 'INV%d' % self.id > > But you wouldn't be able to search for the full INV0000001 string, you > would have to strip the INV beforehand or create a new charfield and > populate that on save (sounds like what you're doing) > > If you don't want to have such obvious incrementing values for your > invoice numbers, you could use a perfect hash function to convert it > to a more obscure value, likehttp://www.djangosnippets.org/snippets/1249/(I > wrote this snippet, > don't worry that two people voted against it, they didn't say why... I > have no idea... it's just a simple perfect hash function and base > converter, and it certainly does the job it was designed to do) > > Cheers, > > Will --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
