Django Model: drop a field

Question

Is there a straightforward clean way to drop a field from Django model? for addition of a field, migrate works perfect but its not working for deletion throwing the following error

django.db.utils.DatabaseError: (1060, "Duplicate column name 'xyz_json_old'")

Answer 1

If you want to drop only the field from the model try this

$ python manage.py dbshell 

You will get directly within your database shell (mysql or psql) it up to what database you are using.

$ mysql> | psql> ALTER TABLE <table_name> DROP column <COLUMN_NAME>;

Open the model too (the python file)and take off the field name from the model and type now

$ python manage.py syncdb

And it will drop the column to from table, doesn't matter if the table is already populated or not.

Answer 2

I am using south but still I had to go through the following with the help of my friend -

He says I must have botched up something and some internal steps in south are not atomic

1. edit the models.py file and delete the column from the class
2. BASH PROMPT$ python manage.py schemamigration core --auto
3. MYSQL PROMPT> alter table core_tablename drop column xyz_json_old; commit;
4. BASH PROMPT$ python manage.py core

Answer 3

You can use South.

• Edit your settings.py and put 'south' into INSTALLED_APPS (assuming you’ve installed it to the right place)
• Run ./manage.py syncdb to load the South table into the database. Note that syncdb looks different now - South modifies it.
• Run ./manage.py convert_to_south myapp -South will automatically make and pretend to apply your first migration.

Then edit your models.py, and then

./manage.py schemamigration --auto myapp

them migrate:

./manage.py migrate myapp