Question

I am using Django with Postgres and Heroku. and I have a post table with looks something like this.

 class Post( models.Model ):
       .
       .
       content1 = models.CharField(max_length=1000)
       .

One of my friends told me that limit is too small, now I want to change that maxlength to 10000. One way I can think of alternating the table by creating a new column named content2 then copying the content from content1, then deleting content1. I am fairly new to this and was wondering what was the best way to approach this problem.

Also is 10000 is a good length for a blog post? 😀

Answer 1

You can either use dumpdata to save the data to a json-file and reload it after you re-create it, you can also manually ALTER the table with the new parameters. Or you can use south.

South provides databas migrations (as its called to change a table layout) for django.

pip install south

Add south to INSTALLED_APPS then run

python manage.py schemamigration --initial your_app_name
python manage.py migrate --fake your_app_name

Do your changes to the models.py, then run

python manage.py schemamigration --auto your_app_name
python manage.py migrate your_app_name

Now if you have the same database layout to change on several machines, check in the created migrations-files to git and run the “migrate” commands on all the machines that needs to update.