Django: Convert CharField to TextField with data intact

Question

Is there a way to change a CharField to a TextField and keep the data from this column intact?

Right now I have the following:

class TestLog(models.Mod         


        

Answer 1

Off hand, I would continue to look into a South approach. This is the workflow that I would try:

1) South schema migration to create two new TextField fields called something like "failed_reqs_txt" and "passed_reqs_txt".

2) Create a data migration to migrate the data from the old fields to the new fields

3) Create a schema migration to delete the original "failed_reqs" and "passed_reqs" fields.

---- if you need the fields to be the same name as the original, I would then proceed to:

4) Create a schema migration to add "failed_reqs", and "passed_reqs" as TextFields

5) Create a data migration to migrate from the "failed_reqs_txt" and "passed_reqs_txt" to the "failed_reqs", and "passed_reqs" fields.

6) Create a schema migration to drop the "failed_reqs_txt" and "passed_reqs_txt" fields.

Though this is a lot of migrations, it breaks up each change into atomic migrations. I'd try this first. I'm not sure why South would be dropping and recreating the db. Did you run the convert_to_south option when adding south to your project? I think this fakes a migration and lets south know that it's working with an existing project and not a new one.

As an alternative, you could do some direct ALTERS to the database to alter the column type and then update the model.py from CharField to TextField. Postgres, supposedly supports implicitly changing data types this way. (See Section 5.5.6.) I'm not sure about mysql, but I think it works the same. (CharField to TextFiled should be a compatible conversion)

Regardless, I'd backup my data before making any such changes. Hope this helps.