Is there a way to define a couple of fields as unique in Django?
I have a table of volumes (of journals) and I don't want more then one volume number for the same journal.
class Volume(models.Model):
id = models.AutoField(primary_key=True)
journal_id = models.ForeignKey(Journals, db_column='jid', null=True, verbose_name = "Journal")
volume_number = models.CharField('Volume Number', max_length=100)
comments = models.TextField('Comments', max_length=4000, blank=True)
I tried to put unique = True
as attribute in the fields journal_id
and volume_number
but it doesn't work.
There is a simple solution for you called unique_together which does exactly what you want.
For example:
class MyModel(models.Model):
field1 = models.CharField(max_length=50)
field2 = models.CharField(max_length=50)
class Meta:
unique_together = ('field1', 'field2',)
And in your case:
class Volume(models.Model):
id = models.AutoField(primary_key=True)
journal_id = models.ForeignKey(Journals, db_column='jid', null=True, verbose_name = "Journal")
volume_number = models.CharField('Volume Number', max_length=100)
comments = models.TextField('Comments', max_length=4000, blank=True)
class Meta:
unique_together = ('journal_id', 'volume_number',)