[Answer]-Save duplicated records in Django

In the DetailLoad model you are setting Proveedor ForeignKey and also making it a primary key. The primary keys are always unique that is why you can not add another entry. You need to remove the primary_key=True from:

id_proveedor = models.ForeignKey(Proveedor,db_column='id_proveedor', primary_key=True, verbose_name='Proveedor')

In django the primary keys are automatically generated and you don’t need to define them in your models. The primary keys can be accessed with id or pk attribute.