django custom relationship field

[bilnus1111]

helo; supose i've tow models:

class Product(models.Model):
ref= models.CharField(max_length=12, unique=True)
code_prod= models.CharField(max_length=50)
description= models.CharField(max_length=150)

class Detail(models.Model):
ref = models.CharField(max_length=10)
year= models.IntegerField()
code = models.CharField(max_length=10)
month = models.IntegerField()
created_at = models.DateField()

class Meta:
    db_table = 'details'

to make oneToMany relationship on Detail model, we can use ForeignKey. this supose in Detail table there is column named product_id,
i want know if i can use another field for example "ref" to make this relationship ?
also how can i perform this SQL query :
query = "select product.ref, product.description, details.year, details.code from product left join details on details.ref = product.ref where product.code = 'abcd' ; "
thank you very much.

[rigor789]

@bilnus1111 I believe you've posted this to the wrong repository. Perhaps https://github.com/django/django ?