hi!
I'm putting together a simple model in Django as an example for a
large project. I'm attempting to set up the models in an efficient
manner with as little redundancy as possible (none).
What I'm attempting to do is use unique_together across 2 classes
which are linked through their primary key fields, with the
unique_together referencing a field from each table which are not the
primary keys.
Is it possible to use unique_together across classes like this? If
not, what alternative could I use that's clean and efficient?
The rules that need to be adherred to within the model are as follows:
1.Survey's have many Lots.
2.Within a Survey, Lot numbers must be unique.
3.Lot's have many Lines.
4.Within a Survey, Line numbers must be unique.
The models are posted below with the fields in question in bold.
class Survey(models.Model):
survey = models.IntegerField(primary_key=True, unique = True)
class Meta:
ordering = ["survey"]
db_table='survey'
class Lot(models.Model):
lot_id = models.AutoField(primary_key=True, unique = True)
lot_number = models.IntegerField()
survey = models.ForeignKey(Survey, db_column ='survey')
class Meta:
ordering = ["lot_number"]
db_table='lot'
unique_together = ("lot_number", "survey")
class Line(models.Model):
line_id = models.AutoField(primary_key=True, unique = True)
lot_id = models.ForeignKey(Lot, db_column='lot_id')
line_number = models.IntegerField()
class Meta:
ordering = ["line_number"]
db_table='line'
unique_together =[("Lot.survey"), ("line_number")]
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