Re: primary key auto increment with PostgreSQL and non Django standard column name

Doesn't autofield with primary_key=True handle this for you (instead of
making it an IntegerField):

https://docs.djangoproject.com/en/1.3/ref/models/fields/#autofield

Hope this helps!
Casey

On 05/27/2011 07:22 PM, Naoko Reeves wrote:
> Hi, I have a Django newbie question.
> My goal is to auto increment primary key with non Django standard column
> name.
> We are converting from existing database and primary key schema is
> "tablename_key" and not "id".
> I googled it and end up reaching to this ticket:
> https://code.djangoproject.com/ticket/13295
> So I understand that there is work in progress but I wanted find work
> around..
>
> 1. My first try was to let postgres handle it.
>
> my postgreSQL table looks like this:
>
> CREATE TABLE poll
> (
> poll_key integer NOT NULL DEFAULT nextval('poll_key_seq'::regclass),
> poll_question character varying(200) NOT NULL,
> poll_pub_date timestamp with time zone NOT NULL,
> CONSTRAINT poll_pkey PRIMARY KEY (poll_key)
> )
>
> My model look like this:
> class Poll(models.Model):
> poll_key = models.IntegerField(primary_key=True)
> poll_question = models.CharField(max_length=200, default='')
> poll_pub_date = models.DateTimeField('date published',
> default=datetime.date.today())
> class Meta:
> db_table = u'poll'
>
> I was hoping that with this, I could
> p = Poll(poll_question="Question 1?")
> p.save()
>
> but this fails because Django is actually sending the following statement:
> INSERT INTO "poll" ("poll_key", "poll_question", "poll_pub_date")
> VALUES (NULL, 'Question 1?', NULL)
>
>
> 2. My Second attempt is then to add default to model
>
> Created a function to return sequence value
> from django.db import connection
> def c_get_next_key(seq_name):
> """ return next value of sequence """
> c = connection.cursor()
> c.execute("SELECT nextval('%s')" % seq_name)
> row = c.fetchone()
> return int(row[0])
>
> Calling like below works just fine. Everytime I call it, I get new number.
> c_get_next_key('poll_key_seq')
>
> Then I modify Poll_key in Poll model as follows:
> Poll_key = models.IntegerField(primary_key=True,
> default=c_get_next_key('poll_key_seq'))
>
> I went to Django Shell and created first record.
> p1 = Poll(poll_question="P1")
> p1.poll_key
> # this will return let's say 37
> p1.save()
> # saves just fine.
>
> # instantiating new object
> p2 = Poll(poll_question="P2")
> p2.poll_key
> # this also return 37.
>
> I know I must be doing something wrong... but could you pint me to right
> direction? I am expecting p2.poll_key to return 38.
> Thank you very much for your help in advance.
>
> Naoko
>
>
>
>
>
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