This project allows you to make Django model changes without having to drop and re-add tables. This project started as a Google Summer of Code project in 2006.
To start using deseb, add the import deseb line after you set DJANGO_SETTINGS_MODULE
in your manage.py. Like this:
#!/usr/bin/env python
import os
import sys
if __name__ == "__main__":
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "myproject.settings")
import deseb # <-- ADD THIS LINE
from django.core.management import execute_from_command_line
execute_from_command_line(sys.argv)Let's say I have the following model:
class Review(models.Model):
when = models.DateTimeField(default=datetime.datetime.now)
text = models.TextField(blank=True, null=True)
rating = models.IntegerField(default=0)
appt = models.ForeignKey(Appointment)
user = models.ForeignKey(User)
uuid = UUIDField(version=4)And I want to add a new column response:
class Review(models.Model):
when = models.DateTimeField(default=datetime.datetime.now)
text = models.TextField(blank=True, null=True)
response = models.TextField(blank=True, null=True)
rating = models.IntegerField(default=0)
appt = models.ForeignKey(Appointment)
user = models.ForeignKey(User)
uuid = UUIDField(version=4)If I run ./manage.py evolvedb, I'll see:
$ ./manage.py evolvedb
appthub: the following schema upgrade is available:
ALTER TABLE `appthub_review` ADD COLUMN `response` longtext;
do you want to run the preceeding commands?
type 'yes' to continue, or 'no' to cancel: yes
schema upgrade executedNow suppose I changed my mind on what that column should be called - it should be response_text:
class Review(models.Model):
when = models.DateTimeField(default=datetime.datetime.now)
text = models.TextField(blank=True, null=True)
response_text = models.TextField(blank=True, null=True, aka='response')
rating = models.IntegerField(default=0)
appt = models.ForeignKey(Appointment)
user = models.ForeignKey(User)
uuid = UUIDField(version=4)Now I run ./manage.py evolvedb again:
$ ./manage.py evolvedb
appthub: the following schema upgrade is available:
ALTER TABLE `appthub_review` CHANGE COLUMN `response` `response_text` longtext NULL;
do you want to run the preceeding commands?
type 'yes' to continue, or 'no' to cancel: yes
schema upgrade executedNow supposed I thought this was a bad idea to begin with, so I change my model back to its original form:
class Review(models.Model):
when = models.DateTimeField(default=datetime.datetime.now)
text = models.TextField(blank=True, null=True)
rating = models.IntegerField(default=0)
appt = models.ForeignKey(Appointment)
user = models.ForeignKey(User)
uuid = UUIDField(version=4)Now run ./manage.py evolvedb again:
$ ./manage.py evolvedb
appthub: the following schema upgrade is available:
-- warning: the following may cause data loss
ALTER TABLE `appthub_review` DROP COLUMN `response_text`;
-- end warning
do you want to run the preceeding commands?
type 'yes' to continue, or 'no' to cancel: yes
schema upgrade executed