#32634: AlterField drops contraints in the wrong order when performed as reverse
migration
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Reporter: Matthias Dellweg | Owner: nobody
Type: Bug | Status: closed
Component: Migrations | Version: 3.2
Severity: Normal | Resolution: invalid
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Matthias Dellweg):
Thanks for you answer, Mariusz.
I do not think that this solves the problem. Yes the migration was
handcrafted (well heavily modified), but autogenerating it was impossible
without providing a default value for what is supposed to be the new
primary key of the model.
So with actual ojects of that Child model, what you need to do is:
1. Add the new secondbase_ptr (as null and not and index)
2. Migrate all associated objects from FirstBase to SecondBase and make
secondbase_ptr reference them (This is where RunPython comes to the play)
3. Remove the firstbase_ptr (to make place for another primary key)
4. Alter secondbase_ptr to not-null and being the primary key.
My best way to resolve this results in the question: Can i call AlterField
in a way to turn the primary key into a common field? Or is there another
way to pivot the primary key?
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Ticket URL: <https://code.djangoproject.com/ticket/32634#comment:4>
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