I have a ManyToManyField using through:

class Entity(models.Model):
    relationships = models.ManyToManyField('self', through='ThroughRelationship', blank=True)
        
class ThroughRelationship(models.Model):
    entity = models.ForeignKey(Entity, on_delete=models.CASCADE)
    name = models.CharField()

I'm adding it to admin like this:

class ThroughRelationshipInline(admin.TabularInline):
    model = ThroughRelationship
    extra = 3

@admin.register(Entity)
class EntityAdmin(admin.ModelAdmin):
    inlines = [ThroughRelationshipInline]

However, in the admin panel, only the name field is showing, I can't select an entity. How can I fix this?

I have a ManyToManyField using through:

class Entity(models.Model):
    relationships = models.ManyToManyField('self', through='ThroughRelationship', blank=True)
        
class ThroughRelationship(models.Model):
    entity = models.ForeignKey(Entity, on_delete=models.CASCADE)
    name = models.CharField()

I'm adding it to admin like this:

class ThroughRelationshipInline(admin.TabularInline):
    model = ThroughRelationship
    extra = 3

@admin.register(Entity)
class EntityAdmin(admin.ModelAdmin):
    inlines = [ThroughRelationshipInline]

However, in the admin panel, only the name field is showing, I can't select an entity. How can I fix this?

• django
• django-admin
• manytomanyfield

• The ThroughRelationShip does not seem to make much sense, if it is a reference to self, it still should require two ForeignKeys. – willeM_ Van Onsem Commented 2 days ago

1 Answer 1

The ThroughRelationShip does not make much sense. Even if you have a ManyToManyField to the same model, it should imply two ForeignKeys, since the ThroughRelationShip is essentially a "junction table" that links two entities together, so:

class Entity(models.Model):
    relationships = models.ManyToManyField('self', through='ThroughRelationship', blank=True)
        
class ThroughRelationship(models.Model):
    entity_from = models.ForeignKey(Entity, on_delete=models.CASCADE, related_name='relations_by_from')
    entity_to = models.ForeignKey(Entity, on_delete=models.CASCADE, related_name='relations_by_to')
    name = models.CharField()

and then work with:

class ThroughRelationshipInline(admin.TabularInline):
    model = ThroughRelationship
    extra = 3
    fk_name = 'entity_from'

@admin.register(Entity)
class EntityAdmin(admin.ModelAdmin):
    inlines = [ThroughRelationshipInline]