How to Create an Auto Incrementing Integer Field

[Cody Scott]

I have a list of articles and you can control the order of the articles by changing the order field in the model

order = models.IntegerField(default=1)

I would like it to default to one more than the last article or one more than the largest order (since you can set the order)

I can't use AutoField because it is only for primary keys.

[Rafael E. Ferrero]

Maybe extending save() method ?

Somethin like...

class your_model(models.Model):

    order = models.IntegerField(default=1)

    def save(self, *args, **kwargs):

        if not self.id:

            #here must to find the last order then sum one and save the result

            self.order=result

        super(your_model, self).save(*args,**kwargs)

       

I'm not quite sure, but i think that this is the way.

2013/7/19 Cody Scott <cody.j....@gmail.com>

--
You received this message because you are subscribed to the Google Groups "Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to django-users...@googlegroups.com.
To post to this group, send email to django...@googlegroups.com.
Visit this group at http://groups.google.com/group/django-users.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

--
Rafael E. Ferrero
Claro: (03562) 15514856

[Christian Erhardt]

Have a look at this post: http://stackoverflow.com/questions/3123796/how-to-make-an-auto-filled-and-auto-incrementing-field-in-django-admin

 

They determine the next value by calling a function called number(). In your case it would look something like this:

class Cliente(models.Model):

    """This is the client data model, it holds all client information. This

       docstring has to be improved."""

    def number():

        no = Cliente.objects.all().aggregate(Max(order))

        if no == None:

            return 1

        else:

            return no + 1

    clientcode = models.IntegerField(_('Code'), max_length=6, unique=True, \

    default=number)

 

[Cody Scott]

Thank you very much, that was exactly what I was looking for.

[Christian Erhardt]

you are very welcome

[Gabriel - Iulian Dumbrava]

I ended up using a stored procedure for something similar, triggered on after insert.