[Django]-Add non-null and unique field with already populated model


Unfortunatelly, I found no answer but I could create one solution:

  • First I have created a migration that allows the slug field to be nullable;
  • Then I have created another migration that populates the slug column with proper values to every row in the model;
  • Then another migration which adds the not-null constraint in the column.


You do your model changes (add field, change, etc), then you call manage.py makemigrations, then apply the migrations with manage.py migrate

You can add the field with null=True, then you e.g. make a script to populate it one time

Otherwise, if you need to populate the field within the migration you can write a custom one, see https://docs.djangoproject.com/en/1.7/ref/migration-operations/#writing-your-own


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