Django CharField not being inserted correctly in MySQL - django

Question

I would like to save phone numbers (US) in the database via Django. I have
from django.db import models
class Number(models.Model):
phone_number = models.CharField("Phone Number", max_length=10, unique=True)
When I ran:
python manage.py sql myapp
I got
BEGIN;
CREATE TABLE `demo_number` (
`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY,
`phone_number` varchar(10) NOT NULL UNIQUE
)
;
When I validate it, there was no error.
python manage.py validate
0 errors found
So I did
python manage.py syncdb
In MySQL console, I see:
mysql> select * from myapp_number;
Empty set (0.00 sec)
mysql> describe myapp_number;
+--------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+-------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| phone_number | varchar(10) | NO | UNI | NULL | |
+--------------+-------------+------+-----+---------+----------------+
2 rows in set (0.03 sec) `
Then in python manage.py shell, I do
from demo.models import Message, Number, Relationship, SmsLog
n=Number(phone_number='1234567890')
n.save()
When I check again in MySQL console, I see:
mysql> select * from myapp_number;
+------------+--------------+
| id | phone_number |
+------------+--------------+
| 2147483647 | 1234567890 |
+------------+--------------+
1 row in set (0.01 sec)
Why is the id a big number? In fact, because of that I cannot insert phone numbers anymore. For example, in python manage.py shell
n=Number(phone_number='0987654321')
n.save()
IntegrityError: (1062, "Duplicate entry '2147483647' for key 'PRIMARY'")
I am new to Django (using Django 1.5 and MySQL Server version: 5.1.63). If someone could point out the obvious mistake I'm making, I would very much appreciate that. On a side note, if I would like to extend the max_length of the CharField to 15, what is the simplest and cleanest (that is, not screwing up the existing set up) way to accomplish that? Thank you.

Answer 1

I can't see any mistakes in your code. If you don't have any data in the table, I would try dropping the demo_number table and running syncdb again.
If you don't have any data in the table, the easiest way to change to max length 15 is to change the model, drop the table in the db shell, then run syncdb again.
If you do have data in the table, you can change the model, then update column in the db. In your case (MySQL specific):
ALTER TABLE demo_number CHANGE phone_number phone_number varchar(15) NOT NULL UNIQUE;
For more complex migrations in Django, use South.

Answer 2

Turns out #Alasdair is right. I had to reset the app. In case anyone is wondering how to do it (I searched in StackOverflow, but might as well post it here since it's relevant), this https://stackoverflow.com/a/15444900/1330974 will work for Django >1.3.
My follow-up question is if the AutoField ID is incremented in case of error. For example, I did this in the shell:
from demo.models import Number
n=Number(phone_number='1234567890')
n.save()
n=Number(phone_number='1234567890')
n.save()
Got an IntegrityError as expected. So try a new number:
n=Number(phone_number='0987654321')
n.save()
Now when I check MySQL console, I see:
mysql> select * from demo_number;
+----+--------------+
| id | phone_number |
+----+--------------+
| 3 | 0987654321 |
| 1 | 1234567890 |
+----+--------------+
2 rows in set (0.00 sec)
Is that normal for Django to skip an ID in AutoField if there is an error? Thank you.