Django migration error :you cannot alter to or from M2M fields, or add or remove through= on M2M fields

Question

I'm trying to modify a M2M field to a ForeignKey field. The command validate shows me no issues and when I run syncdb :

ValueError: Cannot alter field xxx into yyy they are not compatible types (you cannot alter to or from M2M fields, or add or remove through= on M2M fields) 

So I can't make the migration.

class InstituteStaff(Person):     user                 = models.OneToOneField(User, blank=True, null=True)     investigation_area   = models.ManyToManyField(InvestigationArea, blank=True,)     investigation_group  = models.ManyToManyField(InvestigationGroup, blank=True)     council_group        = models.ForeignKey(CouncilGroup, null=True, blank=True)     #profiles            = models.ManyToManyField(Profiles, null = True, blank = True)     profiles             = models.ForeignKey(Profiles, null = True, blank = True) 

This is my first Django project so any suggestions are welcome.

Answer 1

I stumbled upon this and although I didn't care about my data much, I still didn't want to delete the whole DB. So I opened the migration file and changed the AlterField() command to a RemoveField() and an AddField() command that worked well. I lost my data on the specific field, but nothing else.

I.e.

migrations.AlterField(     model_name='player',     name='teams',     field=models.ManyToManyField(related_name='players', through='players.TeamPlayer', to='players.Team'), ), 

to

migrations.RemoveField(     model_name='player',     name='teams', ), migrations.AddField(     model_name='player',     name='teams',     field=models.ManyToManyField(related_name='players', through='players.TeamPlayer', to='players.Team'), ),