如何在Django中不同模型的任何两个字段之间建立OneToOne关系？

Question

class HmsMedicine(models.Model):
    id = models.IntegerField(primary_key=True)
    medicine_name = models.CharField(max_length=100)
    price = models.IntegerField(max_length=6)

class HmsBilling(models.Model):
    id = models.IntegerField(primary_key=True)
    regid = models.ForeignKey(HmsPatient, db_column='regid')
    medicine = models.ForeignKey(HmsMedicine, db_column='medicine')
    quantity = models.IntegerField()
    rate = models.IntegerField()

I want to have the values of price field in the rate field.

Answer 1

class HmsBilling(models.Model):
    id = models.IntegerField(primary_key=True)
    regid = models.ForeignKey(HmsPatient, db_column='regid')
    medicine = models.ForeignKey(HmsMedicine, db_column='medicine')
    quantity = models.IntegerField()
    rate = models.ForeignKey(HmsMedicine, db_column='price')

hms = HmsBilling.objects.select_related().get(id=5)
hms.rate

this will give you the price for the billing with id = 5 (see this link for reference on select related)

better:

class HmsBilling(models.Model):
    id = models.IntegerField(primary_key=True)
    medicine = models.ForeignKey(HmsMedicine)
    quantity = models.IntegerField()

hms = HmsBilling.objects.select_related().get(id=5)
hms.medicine.price