Django + South - migration can't cast the column type - wants me to use "USING"
This was my dirty hack:
- Manually added a migraton for removing the offendig field i.e
migrations.RemoveField( model_name='name_of_the_model', name='offending_field', )2. Then I changed the operation of the complaining migration from AlterField to AddField i.e
migrations.AddField( model_name='name_of_model', name='name_of_field', field=models.ForeignKey(blank=True, null=True, to='ForeignKeyModel'), preserve_default=False, ),```
You have to substitute original db.alter_column with a db.execute:
# Changing field 'MyTable.associated'# db.alter_column(u'data_mytable', 'associated', # self.gf('django.db.models.fields.IntegerField')()# )db.execute( 'ALTER TABLE "data_mytable" ' 'ALTER COLUMN "associated" DROP DEFAULT, ' 'ALTER COLUMN "associated" DROP NOT NULL, ' 'ALTER COLUMN "associated" TYPE INTEGER ' 'USING ' 'CASE ' ' WHEN FALSE THEN 0 ELSE 1 ' 'END') Of course, WHEN condition may change depending of the associated original type.
See also this link.