SQL commands generated in Django by running sqlall

In my Django app, I just ran

$ python manage.py sqlall

and I see a lot of SQL statements that look like this, when describing FK r开发者_JAVA百科elationships:

ALTER TABLE `app1_model1` ADD CONSTRAINT model2_id_refs_id_728de91f FOREIGN KEY (`model2_id`) REFERENCES `app1_model2` (`id`);

Where does "7218de91f" come from? I would like to know because I'd like to manually write SQL statements to accompany models changes in the app so that my db's can be kept up to date.

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Why not use a migration app to write all your SQL for you. It's definitely the smart way to go. Check out South -- part of it will be merged into Django core soon